El Giganto Depot database dialects support from Zell. PostgresSQL here we

come. Automatic schema migration is currently disabled and remains to be
dialectified.

src/java/com/samskivert/jdbc/depot/BindVisitor.java

@@ -0,0 +1,269 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot;
+
+import java.sql.PreparedStatement;
+import java.util.Map;
+
+import com.samskivert.jdbc.depot.Key.WhereCondition;
+import com.samskivert.jdbc.depot.clause.DeleteClause;
+import com.samskivert.jdbc.depot.clause.FieldOverride;
+import com.samskivert.jdbc.depot.clause.ForUpdate;
+import com.samskivert.jdbc.depot.clause.FromOverride;
+import com.samskivert.jdbc.depot.clause.GroupBy;
+import com.samskivert.jdbc.depot.clause.InsertClause;
+import com.samskivert.jdbc.depot.clause.Join;
+import com.samskivert.jdbc.depot.clause.Limit;
+import com.samskivert.jdbc.depot.clause.OrderBy;
+import com.samskivert.jdbc.depot.clause.SelectClause;
+import com.samskivert.jdbc.depot.clause.UpdateClause;
+import com.samskivert.jdbc.depot.clause.Where;
+import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
+import com.samskivert.jdbc.depot.expression.FunctionExp;
+import com.samskivert.jdbc.depot.expression.LiteralExp;
+import com.samskivert.jdbc.depot.expression.SQLExpression;
+import com.samskivert.jdbc.depot.expression.ValueExp;
+import com.samskivert.jdbc.depot.operator.Conditionals.In;
+import com.samskivert.jdbc.depot.operator.Conditionals.IsNull;
+import com.samskivert.jdbc.depot.operator.Conditionals.Match;
+import com.samskivert.jdbc.depot.operator.Logic.Not;
+import com.samskivert.jdbc.depot.operator.SQLOperator.BinaryOperator;
+import com.samskivert.jdbc.depot.operator.SQLOperator.MultiOperator;
+
+/**
+ * Implements the base functionality of the argument-binding pass of {@link SQLBuilder}. Dialectal
+ * subclasses of this should be created and returned from {@link SQLBuilder#getBindVisitor()}.
+ *
+ * This class is intimately paired with {#link BuildVisitor}.
+ */
+public class BindVisitor implements ExpressionVisitor
+{
+    public void visit (FromOverride override)
+        throws Exception
+    {
+    }
+
+    public void visit (FieldOverride fieldOverride)
+        throws Exception
+    {
+    }
+
+    public void visit (WhereCondition<? extends PersistentRecord> whereCondition)
+        throws Exception
+    {
+        Comparable[] values = whereCondition.getValues();
+        for (int ii = 0; ii < values.length; ii ++) {
+            if (values[ii] != null) {
+                _stmt.setObject(_argIdx ++, values[ii]);
+            }
+        }
+    }
+
+    public void visit (Key key)
+        throws Exception
+    {
+        key.condition.accept(this);
+    }
+
+    public void visit (MultiKey<? extends PersistentRecord> key)
+        throws Exception
+    {
+        for (Map.Entry entry : key.getSingleFieldsMap().entrySet()) {
+            if (entry.getValue() != null) {
+                _stmt.setObject(_argIdx ++, entry.getValue());
+            }
+        }
+        Comparable[] values = key.getMultiValues();
+        for (int ii = 0; ii < values.length; ii++) {
+            _stmt.setObject(_argIdx ++, values[ii]);
+        }
+    }
+
+    public void visit (FunctionExp functionExp)
+        throws Exception
+    {
+        visit(functionExp.getArguments());
+    }
+
+    public void visit (MultiOperator multiOperator)
+        throws Exception
+    {
+        visit(multiOperator.getConditions());
+    }
+
+    public void visit (BinaryOperator binaryOperator) throws Exception
+    {
+        binaryOperator.getLeftHandSide().accept(this);
+        binaryOperator.getRightHandSide().accept(this);
+    }
+
+    public void visit (IsNull isNull) throws Exception
+    {
+    }
+
+    public void visit (In in) throws Exception
+    {
+        Comparable[] values = in.getValues();
+        for (int ii = 0; ii < values.length; ii++) {
+            _stmt.setObject(_argIdx ++, values[ii]);
+        }
+    }
+
+    public void visit (Match match) throws Exception
+    {
+        // we never get here
+    }
+
+    public void visit (ColumnExp columnExp) throws Exception
+    {
+        // no arguments
+    }
+
+    public void visit (Not not) throws Exception
+    {
+        not.getCondition().accept(this);
+    }
+
+    public void visit (GroupBy groupBy) throws Exception
+    {
+        visit(groupBy.getValues());
+    }
+
+    public void visit (ForUpdate forUpdate) throws Exception
+    {
+        // do nothing
+    }
+
+    public void visit (OrderBy orderBy) throws Exception
+    {
+        visit(orderBy.getValues());
+    }
+
+    public void visit (Where where) throws Exception
+    {
+        where.getCondition().accept(this);
+    }
+
+    public void visit (Join join) throws Exception
+    {
+        join.getJoinCondition().accept(this);
+    }
+
+    public void visit (Limit limit) throws Exception
+    {
+        _stmt.setObject(_argIdx++, limit.getCount());
+        _stmt.setObject(_argIdx++, limit.getOffset());
+    }
+
+    public void visit (LiteralExp literalExp) throws Exception
+    {
+        // do nothing
+    }
+
+    public void visit (ValueExp valueExp) throws Exception
+    {
+        // workaround for postgres bug, fixed in next release:
+        // http://archives.postgresql.org/pgsql-jdbc/2007-06/msg00080.php
+        if (valueExp.getValue() instanceof Byte) {
+            _stmt.setByte(_argIdx ++, (Byte) valueExp.getValue());
+        } else {
+            _stmt.setObject(_argIdx ++, valueExp.getValue());
+        }
+    }
+
+    public void visit (SelectClause<? extends PersistentRecord> selectClause)
+        throws Exception
+    {
+        for (Join clause : selectClause.getJoinClauses()) {
+            clause.accept(this);
+        }
+        if (selectClause.getWhereClause() != null) {
+            selectClause.getWhereClause().accept(this);
+        }
+        if (selectClause.getGroupBy() != null) {
+            selectClause.getGroupBy().accept(this);
+        }
+        if (selectClause.getOrderBy() != null) {
+            selectClause.getOrderBy().accept(this);
+        }
+        if (selectClause.getLimit() != null) {
+            selectClause.getLimit().accept(this);
+        }
+        if (selectClause.getForUpdate() != null) {
+            selectClause.getForUpdate().accept(this);
+        }
+    }
+
+    public void visit (UpdateClause<? extends PersistentRecord> updateClause) throws Exception
+    {
+        DepotMarshaller marsh = _types.getMarshaller(updateClause.getPersistentClass());
+
+        // bind the update arguments
+        String[] fields = updateClause.getFields();
+        Object pojo = updateClause.getPojo();
+        if (pojo != null) {
+            for (int ii = 0; ii < fields.length; ii ++) {
+                marsh.getFieldMarshaller(fields[ii]).readFromObject(pojo, _stmt, _argIdx++);
+            }
+        } else {
+            visit(updateClause.getValues());
+        }
+        updateClause.getWhereClause().accept(this);
+    }
+
+    public void visit (DeleteClause<? extends PersistentRecord> deleteClause) throws Exception
+    {
+        deleteClause.getWhereClause().accept(this);
+    }
+
+    public void visit (InsertClause<? extends PersistentRecord> insertClause) throws Exception
+    {
+        DepotMarshaller marsh = _types.getMarshaller(insertClause.getPersistentClass());
+
+        Object pojo = insertClause.getPojo();
+        String ixField = insertClause.getIndexField();
+        for (String field : marsh.getColumnFieldNames()) {
+            if (ixField == null || !ixField.equals(field)) {
+                marsh.getFieldMarshaller(field).readFromObject(pojo, _stmt, _argIdx ++);
+            }
+        }
+    }
+
+    protected BindVisitor (DepotTypes types, PreparedStatement stmt)
+    {
+        _types = types;
+        _stmt = stmt;
+        _argIdx = 1;
+    }
+
+    protected void visit (SQLExpression[] expressions)
+        throws Exception
+    {
+        for (int ii = 0; ii < expressions.length; ii ++) {
+            expressions[ii].accept(this);
+        }
+    }
+
+    protected DepotTypes _types;
+    protected PreparedStatement _stmt;
+    protected int _argIdx;
+}

src/java/com/samskivert/jdbc/depot/BuildVisitor.java

@@ -0,0 +1,516 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot;
+
+import java.sql.SQLException;
+import java.util.List;
+import java.util.Map;
+
+import com.samskivert.jdbc.depot.Key.WhereCondition;
+import com.samskivert.jdbc.depot.annotation.Computed;
+import com.samskivert.jdbc.depot.clause.DeleteClause;
+import com.samskivert.jdbc.depot.clause.FieldOverride;
+import com.samskivert.jdbc.depot.clause.ForUpdate;
+import com.samskivert.jdbc.depot.clause.FromOverride;
+import com.samskivert.jdbc.depot.clause.GroupBy;
+import com.samskivert.jdbc.depot.clause.InsertClause;
+import com.samskivert.jdbc.depot.clause.Join;
+import com.samskivert.jdbc.depot.clause.Limit;
+import com.samskivert.jdbc.depot.clause.OrderBy;
+import com.samskivert.jdbc.depot.clause.SelectClause;
+import com.samskivert.jdbc.depot.clause.UpdateClause;
+import com.samskivert.jdbc.depot.clause.Where;
+import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
+import com.samskivert.jdbc.depot.expression.FunctionExp;
+import com.samskivert.jdbc.depot.expression.LiteralExp;
+import com.samskivert.jdbc.depot.expression.SQLExpression;
+import com.samskivert.jdbc.depot.expression.ValueExp;
+import com.samskivert.jdbc.depot.operator.Conditionals.In;
+import com.samskivert.jdbc.depot.operator.Conditionals.IsNull;
+import com.samskivert.jdbc.depot.operator.Conditionals.Match;
+import com.samskivert.jdbc.depot.operator.Logic.Not;
+import com.samskivert.jdbc.depot.operator.SQLOperator.BinaryOperator;
+import com.samskivert.jdbc.depot.operator.SQLOperator.MultiOperator;
+
+/**
+ * Implements the base functionality of the SQL-building pass of {@link SQLBuilder}. Dialectal
+ * subclasses of this should be created and returned from {@link SQLBuilder#getBuildVisitor()}.
+ *
+ * This class is intimately paired with {#link BindVisitor}.
+ */
+public abstract class BuildVisitor implements ExpressionVisitor
+{
+    public String getQuery ()
+    {
+        return _builder.toString();
+    }
+
+    public void visit (FromOverride override)
+        throws Exception
+    {
+        _builder.append(" from " );
+        List<Class<? extends PersistentRecord>> from = override.getFromClasses();
+        for (int ii = 0; ii < from.size(); ii++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            appendTableName(from.get(ii));
+            _builder.append(" as ");
+            appendTableAbbreviation(from.get(ii));
+        }
+    }
+
+    public void visit (FieldOverride fieldOverride)
+        throws Exception
+    {
+        fieldOverride.getOverride().accept(this);
+        _builder.append(" as ");
+        appendField(fieldOverride.getField());
+    }
+
+    public void visit (WhereCondition<? extends PersistentRecord> whereCondition)
+        throws Exception
+    {
+        String[] keyFields = Key.getKeyFields(whereCondition.getPersistentClass());
+        Comparable[] values = whereCondition.getValues();
+        for (int ii = 0; ii < keyFields.length; ii ++) {
+            if (ii > 0) {
+                _builder.append(" and ");
+            }
+            appendColumn(whereCondition.getPersistentClass(), keyFields[ii]);
+            _builder.append(values[ii] == null ? " is null " : " = ? ");
+        }
+    }
+
+    public void visit (Key key)
+        throws Exception
+    {
+        _builder.append(" where ");
+        key.condition.accept(this);
+    }
+
+    public void visit (MultiKey<? extends PersistentRecord> key)
+        throws Exception
+    {
+        _builder.append(" where ");
+        boolean first = true;
+        for (Map.Entry<String, Comparable> entry : key.getSingleFieldsMap().entrySet()) {
+            if (first) {
+                first = false;
+            } else {
+                _builder.append(" and ");
+            }
+            appendColumn(key.getPersistentClass(), entry.getKey());
+            _builder.append(entry.getValue() == null ? " is null " : " = ? ");
+        }
+        if (!first) {
+            _builder.append(" and ");
+        }
+        appendColumn(key.getPersistentClass(), key.getMultiField());
+        _builder.append(" in (");
+
+        Comparable[] values = key.getMultiValues();
+        for (int ii = 0; ii < values.length; ii ++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            _builder.append("?");
+        }
+        _builder.append(")");
+    }
+
+    public void visit (FunctionExp functionExp)
+        throws Exception
+    {
+        _builder.append(functionExp.getFunction());
+        _builder.append("(");
+        SQLExpression[] arguments = functionExp.getArguments();
+        for (int ii = 0; ii < arguments.length; ii ++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            arguments[ii].accept(this);
+        }
+        _builder.append(")");
+    }
+
+    public void visit (MultiOperator multiOperator)
+        throws Exception
+    {
+        SQLExpression[] conditions = multiOperator.getConditions();
+        for (int ii = 0; ii < conditions.length; ii++) {
+            if (ii > 0) {
+                _builder.append(" ").append(multiOperator.operator()).append(" ");
+            }
+            _builder.append("(");
+            conditions[ii].accept(this);
+            _builder.append(")");
+        }
+    }
+
+    public void visit (BinaryOperator binaryOperator)
+        throws Exception
+    {
+        binaryOperator.getLeftHandSide().accept(this);
+        _builder.append(binaryOperator.operator());
+        binaryOperator.getRightHandSide().accept(this);
+    }
+
+    public void visit (IsNull isNull)
+        throws Exception
+    {
+        isNull.getColumn().accept(this);
+        _builder.append(" is null");
+    }
+
+    public void visit (In in)
+        throws Exception
+    {
+        in.getColumn().accept(this);
+        _builder.append(" in (");
+        Comparable[] values = in.getValues();
+        for (int ii = 0; ii < values.length; ii ++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            _builder.append("?");
+        }
+        _builder.append(")");
+    }
+
+    public void visit (Match match)
+        throws Exception
+    {
+        throw new IllegalArgumentException("Match() is MySQL-specific.");
+    }
+
+    public void visit (ColumnExp columnExp)
+        throws Exception
+    {
+        appendTableAbbreviation(columnExp.getPersistentClass());
+        _builder.append(".");
+        appendColumn(columnExp.getPersistentClass(), columnExp.getField());
+    }
+
+    public void visit (Not not)
+        throws Exception
+    {
+        _builder.append(" not (");
+        not.getCondition().accept(this);
+        _builder.append(")");
+    }
+
+    public void visit (GroupBy groupBy)
+        throws Exception
+    {
+        _builder.append(" group by ");
+
+        SQLExpression[] values = groupBy.getValues();
+        for (int ii = 0; ii < values.length; ii++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            values[ii].accept(this);
+        }
+    }
+
+    public void visit (ForUpdate forUpdate)
+        throws Exception
+    {
+        _builder.append(" for update ");
+    }
+
+    public void visit (OrderBy orderBy)
+        throws Exception
+    {
+        _builder.append(" order by ");
+
+        SQLExpression[] values = orderBy.getValues();
+        OrderBy.Order[] orders = orderBy.getOrders();
+        for (int ii = 0; ii < values.length; ii++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            values[ii].accept(this);
+            _builder.append(" ").append(orders[ii]);
+        }
+    }
+
+    public void visit (Where where)
+        throws Exception
+    {
+        _builder.append(" where ");
+        where.getCondition().accept(this);
+    }
+
+    public void visit (Join join)
+        throws Exception
+    {
+        switch (join.getType()) {
+        case INNER:
+            _builder.append(" inner join " );
+            break;
+        case LEFT_OUTER:
+            _builder.append(" left outer join " );
+            break;
+        case RIGHT_OUTER:
+            _builder.append(" right outer join " );
+            break;
+        }
+        appendTableName(join.getJoinClass());
+        _builder.append(" as ");
+        appendTableAbbreviation(join.getJoinClass());
+        _builder.append(" on ");
+        join.getJoinCondition().accept(this);
+    }
+
+    public void visit (Limit limit)
+        throws Exception
+    {
+        _builder.append(" limit ? offset ? ");
+    }
+
+    public void visit (LiteralExp literalExp)
+        throws Exception
+    {
+        _builder.append(literalExp.getText());
+    }
+
+    public void visit (ValueExp valueExp)
+        throws Exception
+    {
+        _builder.append("?");
+    }
+
+    public void visit (SelectClause<? extends PersistentRecord> selectClause)
+        throws Exception
+    {
+        Class<? extends PersistentRecord> pClass = selectClause.getPersistentClass();
+        boolean isInner = _innerClause;
+        _innerClause = true;
+
+        if (isInner) {
+            _builder.append("(");
+        }
+        _builder.append("select ");
+
+        Computed entityComputed = pClass.getAnnotation(Computed.class);
+
+        // iterate over the fields we're filling in and figure out whence each one comes
+        boolean skip = true;
+        for (String field : selectClause.getFields()) {
+            if (!skip) {
+                _builder.append(", ");
+            }
+            skip = false;
+
+            // first, see if there's a field override
+            FieldOverride override = selectClause.lookupOverride(field);
+            if (override != null) {
+                override.accept(this);
+                continue;
+            }
+
+            // figure out the class we're selecting from unless we're otherwise overriden:
+            // for a concrete record, simply use the corresponding table; for a computed one,
+            // default to the shadowed concrete record, or null if there isn't one
+
+            Class<? extends PersistentRecord> tableClass;
+            if (entityComputed == null) {
+                tableClass = pClass;
+            } else if (!PersistentRecord.class.equals(entityComputed.shadowOf())) {
+                tableClass = entityComputed.shadowOf();
+            } else {
+                tableClass = null;
+            }
+
+            // handle the field-level @Computed annotation, if there is one
+            FieldMarshaller fm = _types.getMarshaller(pClass).getFieldMarshaller(field);
+            if (fm == null) {
+                throw new IllegalArgumentException(
+                    "could not find marshaller for field: " + field);
+            }
+            Computed fieldComputed = fm.getComputed();
+            if (fieldComputed != null) {
+                // check if the computed field has a literal SQL definition
+                if (fieldComputed.fieldDefinition().length() > 0) {
+                    _builder.append(fieldComputed.fieldDefinition()).append(" as ");
+                    appendField(field);
+                    continue;
+                }
+
+                // or if we can simply ignore the field
+                if (!fieldComputed.required()) {
+                    skip = true;
+                    continue;
+                }
+
+                // else see if there's an overriding shadowOf definition
+                if (fieldComputed.shadowOf() != null) {
+                    tableClass = fieldComputed.shadowOf();
+                }
+            }
+
+            // if we get this far we hopefully have a table to select from
+            if (tableClass != null) {
+                appendTableAbbreviation(tableClass);
+                _builder.append(".");
+                appendColumn(tableClass, field);
+                continue;
+            }
+
+            // else owie
+            throw new IllegalArgumentException(
+                "Persistent field has no definition [class=" +
+                selectClause.getPersistentClass() + ", field=" + field + "]");
+        }
+
+        if (selectClause.getFromOverride() != null) {
+            selectClause.getFromOverride().accept(this);
+
+        } else if (_types.getTableName(pClass) != null) {
+            _builder.append(" from ");
+            appendTableName(pClass);
+            _builder.append(" as ");
+            appendTableAbbreviation(pClass);
+
+        } else {
+            throw new SQLException("Query on @Computed entity with no FromOverrideClause.");
+        }
+
+        for (Join clause : selectClause.getJoinClauses()) {
+            clause.accept(this);
+        }
+        if (selectClause.getWhereClause() != null) {
+            selectClause.getWhereClause().accept(this);
+        }
+        if (selectClause.getGroupBy() != null) {
+            selectClause.getGroupBy().accept(this);
+        }
+        if (selectClause.getOrderBy() != null) {
+            selectClause.getOrderBy().accept(this);
+        }
+        if (selectClause.getLimit() != null) {
+            selectClause.getLimit().accept(this);
+        }
+        if (selectClause.getForUpdate() != null) {
+            selectClause.getForUpdate().accept(this);
+        }
+        if (isInner) {
+            _builder.append(")");
+        }
+    }
+
+    public void visit (UpdateClause<? extends PersistentRecord> updateClause)
+        throws Exception
+    {
+        Class<? extends PersistentRecord> pClass = updateClause.getPersistentClass();
+        _innerClause = true;
+
+        _builder.append("update ");
+        appendTableName(pClass);
+        _builder.append(" as ");
+        appendTableAbbreviation(pClass);
+        _builder.append(" set ");
+
+        String[] fields = updateClause.getFields();
+        Object pojo = updateClause.getPojo();
+        SQLExpression[] values = updateClause.getValues();
+        for (int ii = 0; ii < fields.length; ii ++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            appendColumn(pClass, fields[ii]);
+
+            _builder.append(" = ");
+            if (pojo != null) {
+                _builder.append("?");
+            } else {
+                values[ii].accept(this);
+            }
+        }
+        updateClause.getWhereClause().accept(this);
+    }
+
+    public void visit (DeleteClause<? extends PersistentRecord> deleteClause)
+        throws Exception
+    {
+        _builder.append("delete from ");
+        appendTableName(deleteClause.getPersistentClass());
+        _builder.append(" ");
+        deleteClause.getWhereClause().accept(this);
+    }
+
+    public void visit (InsertClause<? extends PersistentRecord> insertClause)
+        throws Exception
+    {
+        Class<? extends PersistentRecord> pClass = insertClause.getPersistentClass();
+        DepotMarshaller marsh = _types.getMarshaller(pClass);
+        _innerClause = true;
+
+        String[] fields = marsh.getColumnFieldNames();
+
+        _builder.append("insert into ");
+        appendTableName(insertClause.getPersistentClass());
+        _builder.append(" (");
+        for (int ii = 0; ii < fields.length; ii ++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            appendColumn(pClass, fields[ii]);
+        }
+        _builder.append(") values(");
+
+        String ixField = insertClause.getIndexField();
+        for (int ii = 0; ii < fields.length; ii++) {
+            if (ii > 0) {
+                _builder.append(", ");
+            }
+            if (ixField != null && ixField.equals(fields[ii])) {
+                _builder.append("DEFAULT");
+            } else {
+                _builder.append("?");
+            }
+        }
+        _builder.append(")");
+    }
+
+    protected abstract void appendTableName (Class<? extends PersistentRecord> type);
+    protected abstract void appendTableAbbreviation (Class<? extends PersistentRecord> type);
+    protected abstract void appendColumn (Class<? extends PersistentRecord> type, String field);
+    protected abstract void appendField (String field);
+
+    protected BuildVisitor (DepotTypes types)
+    {
+        _types = types;
+        _builder = new StringBuilder();
+        _innerClause = false;
+    }
+
+    protected DepotTypes _types;
+
+    /** A StringBuilder to hold the constructed SQL. */
+    protected StringBuilder _builder;
+
+    /** A flag that's set to true for inner SELECT's */
+    protected boolean _innerClause;
+}

src/java/com/samskivert/jdbc/depot/DepotMarshaller.java

@@ -48,11 +48,8 @@ import com.samskivert.jdbc.depot.annotation.TableGenerator;
 import com.samskivert.jdbc.depot.annotation.Transient;
 import com.samskivert.jdbc.depot.annotation.UniqueConstraint;
 
-import com.samskivert.jdbc.JDBCUtil;
-import com.samskivert.jdbc.depot.clause.Where;
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.util.ArrayUtil;
-import com.samskivert.util.ListUtil;
-import com.samskivert.util.StringUtil;
 
 import static com.samskivert.jdbc.depot.Log.log;
 
@@ -75,7 +72,6 @@ public class DepotMarshaller<T extends PersistentRecord>
         _pclass = pclass;
 
         Entity entity = pclass.getAnnotation(Entity.class);
-        Table table = null;
 
         // see if this is a computed entity
         Computed computed = pclass.getAnnotation(Computed.class);
@@ -89,11 +85,7 @@ public class DepotMarshaller<T extends PersistentRecord>
                 if (entity.name().length() > 0) {
                     _tableName = entity.name();
                 }
-                _postamble = entity.postamble();
             }
-
-            // check for a Table annotation, for unique constraints
-            table = pclass.getAnnotation(Table.class);
         }
 
         // if the entity defines a new TableGenerator, map that in our static table as those are
@@ -127,8 +119,8 @@ public class DepotMarshaller<T extends PersistentRecord>
             }
 
             FieldMarshaller fm = FieldMarshaller.createMarshaller(field);
-            _fields.put(fm.getColumnName(), fm);
-            fields.add(fm.getColumnName());
+            _fields.put(field.getName(), fm);
+            fields.add(field.getName());
 
             // check to see if this is our primary key
             if (field.getAnnotation(Id.class) != null) {
@@ -181,7 +173,8 @@ public class DepotMarshaller<T extends PersistentRecord>
                 switch(gv.strategy()) {
                 case AUTO:
                 case IDENTITY:
-                    _keyGenerator = new IdentityKeyGenerator();
+                    _keyGenerator = new IdentityKeyGenerator(
+                        gv, getTableName(), keyField.getColumnName());
                     break;
 
                 case TABLE:
@@ -191,7 +184,8 @@ public class DepotMarshaller<T extends PersistentRecord>
                         throw new IllegalArgumentException(
                             "Unknown generator [generator=" + name + "]");
                     }
-                    _keyGenerator = new TableKeyGenerator(generator);
+                    _keyGenerator = new TableKeyGenerator(
+                        generator, gv, getTableName(), keyField.getColumnName());
                     break;
                 }
             }
@@ -199,54 +193,6 @@ public class DepotMarshaller<T extends PersistentRecord>
 
         // generate our full list of fields/columns for use in queries
         _allFields = fields.toArray(new String[fields.size()]);
-
-        // if we're a computed entity, stop here
-        if (_tableName == null) {
-            return;
-        }
-
-        // figure out the list of fields that correspond to actual table columns and generate the
-        // SQL used to create and migrate our table (unless we're a computed entity)
-        _columnFields = new String[_allFields.length];
-        int jj = 0;
-        for (int ii = 0; ii < _allFields.length; ii++) {
-            // include all persistent non-computed fields
-            String colDef = _fields.get(_allFields[ii]).getColumnDefinition();
-            if (colDef != null) {
-                _columnFields[jj] = _allFields[ii];
-                _declarations.add(colDef);
-                jj ++;
-            }
-        }
-        _columnFields = ArrayUtil.splice(_columnFields, jj);
-
-        // determine whether we have any index definitions
-        if (entity != null) {
-            for (Index index : entity.indices()) {
-                // TODO: delegate this to a database specific SQL generator
-                _declarations.add(index.type() + " index " + index.name() +
-                                  " (" + StringUtil.join(index.columns(), ", ") + ")");
-            }
-        }
-
-        // add any unique constraints given
-        if (table != null) {
-            for (UniqueConstraint constraint : table.uniqueConstraints()) {
-                _declarations.add(
-                    "UNIQUE (" + StringUtil.join(constraint.columnNames(), ", ") + ")");
-            }
-        }
-
-        // add the primary key, if we have one
-        if (hasPrimaryKey()) {
-            _declarations.add("PRIMARY KEY (" + getJoinedKeyColumns() + ")");
-        }
-
-        // if we did not find a schema version field, complain
-        if (_schemaVersion < 0) {
-            log.warning("Unable to read " + _pclass.getName() + "." + SCHEMA_VERSION_FIELD +
-                        ". Schema migration disabled.");
-        }
     }
 
     /**
@@ -266,6 +212,14 @@ public class DepotMarshaller<T extends PersistentRecord>
         return _allFields;
     }
 
+    /**
+     * Returns all the persistent fields that correspond to concrete table columns.
+     */
+    public String[] getColumnFieldNames ()
+    {
+        return _columnFields;
+    }
+
     /**
      * Returns the {@link FieldMarshaller} for a named field on our persistent class.
      */
@@ -283,14 +237,23 @@ public class DepotMarshaller<T extends PersistentRecord>
     }
 
     /**
-     * Return the names of the columns that constitute the primary key of our associated
-     * persistent record.
+     * Returns the {@link KeyGenerator} used to generate primary keys for this persistent object,
+     * or null if it does not use a key generator.
      */
-    public String[] getPrimaryKeyColumns ()
+    public KeyGenerator getKeyGenerator ()
+    {
+        return _keyGenerator;
+    }
+
+    /**
+     * Return the names of the columns that constitute the primary key of our associated persistent
+     * record.
+     */
+    public String[] getPrimaryKeyFields ()
     {
         String[] pkcols = new String[_pkColumns.size()];
         for (int ii = 0; ii < pkcols.length; ii ++) {
-            pkcols[ii] = _pkColumns.get(ii).getColumnName();
+            pkcols[ii] = _pkColumns.get(ii).getField().getName();
         }
         return pkcols;
     }
@@ -359,11 +322,11 @@ public class DepotMarshaller<T extends PersistentRecord>
             throw new UnsupportedOperationException(
                 getClass().getName() + " does not define a primary key");
         }
-        String[] columns = new String[_pkColumns.size()];
+        String[] fields = new String[_pkColumns.size()];
         for (int ii = 0; ii < _pkColumns.size(); ii++) {
-            columns[ii] = _pkColumns.get(ii).getColumnName();
+            fields[ii] = _pkColumns.get(ii).getField().getName();
         }
-        return new Key<T>(_pclass, columns, values);
+        return new Key<T>(_pclass, fields, values);
     }
 
     /**
@@ -416,7 +379,7 @@ public class DepotMarshaller<T extends PersistentRecord>
             // then create and populate the persistent object
             T po = _pclass.newInstance();
             for (FieldMarshaller fm : _fields.values()) {
-                if (!fields.contains(fm.getField().getName())) {
+                if (!fields.contains(fm.getColumnName())) {
                     // this field was not in the result set, make sure that's OK
                     if (fm.getComputed() != null && !fm.getComputed().required()) {
                         continue;
@@ -438,46 +401,6 @@ public class DepotMarshaller<T extends PersistentRecord>
         }
     }
 
-    /**
-     * Creates a statement that will insert the supplied persistent object into the database.
-     */
-    public PreparedStatement createInsert (Connection conn, Object po)
-        throws SQLException
-    {
-        requireNotComputed("insert rows into");
-
-        try {
-            StringBuilder insert = new StringBuilder();
-            insert.append("insert into ").append(getTableName());
-            insert.append(" (").append(StringUtil.join(_columnFields, ","));
-            insert.append(")").append(" values(");
-            for (int ii = 0; ii < _columnFields.length; ii++) {
-                if (ii > 0) {
-                    insert.append(", ");
-                }
-                insert.append("?");
-            }
-            insert.append(")");
-
-            // TODO: handle primary key, nullable fields specially?
-            PreparedStatement pstmt = conn.prepareStatement(insert.toString());
-            int idx = 0;
-            for (String field : _columnFields) {
-                _fields.get(field).readFromObject(po, pstmt, ++idx);
-            }
-            return pstmt;
-
-        } catch (SQLException sqe) {
-            // pass this on through
-            throw sqe;
-
-        } catch (Exception e) {
-            String errmsg = "Failed to marshall persistent object [pclass=" +
-                _pclass.getName() + "]";
-            throw (SQLException)new SQLException(errmsg).initCause(e);
-        }
-    }
-
     /**
      * Fills in the primary key just assigned to the supplied persistence object by the execution
      * of the results of {@link #createInsert}.
@@ -485,7 +408,8 @@ public class DepotMarshaller<T extends PersistentRecord>
      * @return the newly assigned primary key or null if the object does not use primary keys or
      * this is not the right time to assign the key.
      */
-    public Key assignPrimaryKey (Connection conn, Object po, boolean postFactum)
+    public Key assignPrimaryKey (
+        Connection conn, DatabaseLiaison liaison, Object po, boolean postFactum)
         throws SQLException
     {
         // if we have no primary key or no generator, then we're done
@@ -499,7 +423,7 @@ public class DepotMarshaller<T extends PersistentRecord>
         }
 
         try {
-            int nextValue = _keyGenerator.nextGeneratedValue(conn);
+            int nextValue = _keyGenerator.nextGeneratedValue(conn, liaison);
             _pkColumns.get(0).getField().set(po, nextValue);
             return makePrimaryKey(nextValue);
         } catch (Exception e) {
@@ -508,131 +432,6 @@ public class DepotMarshaller<T extends PersistentRecord>
         }
     }
 
-    /**
-     * Creates a statement that will update the supplied persistent object using the supplied key.
-     */
-    public PreparedStatement createUpdate (Connection conn, Object po, Where key)
-        throws SQLException
-    {
-        return createUpdate(conn, po, key, _columnFields);
-    }
-
-    /**
-     * Creates a statement that will update the supplied persistent object
-     * using the supplied key.
-     */
-    public PreparedStatement createUpdate (
-        Connection conn, Object po, Where key, String[] modifiedFields)
-        throws SQLException
-    {
-        requireNotComputed("update rows in");
-
-        StringBuilder update = new StringBuilder();
-        update.append("update ").append(getTableName()).append(" set ");
-        int idx = 0;
-        for (String field : modifiedFields) {
-            if (idx++ > 0) {
-                update.append(", ");
-            }
-            update.append(field).append(" = ?");
-        }
-        key.appendClause(null, update);
-
-        try {
-            PreparedStatement pstmt = conn.prepareStatement(update.toString());
-            idx = 0;
-            // bind the update arguments
-            for (String field : modifiedFields) {
-                _fields.get(field).readFromObject(po, pstmt, ++idx);
-            }
-            // now bind the key arguments
-            key.bindClauseArguments(pstmt, ++idx);
-            return pstmt;
-
-        } catch (SQLException sqe) {
-            // pass this on through
-            throw sqe;
-
-        } catch (Exception e) {
-            String errmsg = "Failed to marshall persistent object " +
-                "[pclass=" + _pclass.getName() + "]";
-            throw (SQLException)new SQLException(errmsg).initCause(e);
-        }
-    }
-
-    /**
-     * Creates a statement that will update the specified set of fields for all persistent objects
-     * that match the supplied key.
-     */
-    public PreparedStatement createPartialUpdate (
-        Connection conn, Where key, String[] modifiedFields, Object[] modifiedValues)
-        throws SQLException
-    {
-        requireNotComputed("update rows in");
-
-        StringBuilder update = new StringBuilder();
-        update.append("update ").append(getTableName()).append(" set ");
-        int idx = 0;
-        for (String field : modifiedFields) {
-            if (idx++ > 0) {
-                update.append(", ");
-            }
-            update.append(field).append(" = ?");
-        }
-        key.appendClause(null, update);
-
-        PreparedStatement pstmt = conn.prepareStatement(update.toString());
-        idx = 0;
-        // bind the update arguments
-        for (Object value : modifiedValues) {
-            // TODO: use the field marshaller?
-            pstmt.setObject(++idx, value);
-        }
-        // now bind the key arguments
-        key.bindClauseArguments(pstmt, ++idx);
-        return pstmt;
-    }
-
-    /**
-     * Creates a statement that will delete all rows matching the supplied key.
-     */
-    public PreparedStatement createDelete (Connection conn, Where key)
-        throws SQLException
-    {
-        requireNotComputed("delete rows from");
-
-        StringBuilder query = new StringBuilder("delete from " + getTableName());
-        key.appendClause(null, query);
-        PreparedStatement pstmt = conn.prepareStatement(query.toString());
-        key.bindClauseArguments(pstmt, 1);
-        return pstmt;
-    }
-
-    /**
-     * Creates a statement that will update the specified set of fields, using the supplied literal
-     * SQL values, for all persistent objects that match the supplied key.
-     */
-    public PreparedStatement createLiteralUpdate (
-        Connection conn, Where key, String[] modifiedFields, Object[] modifiedValues)
-        throws SQLException
-    {
-        requireNotComputed("update rows in");
-
-        StringBuilder update = new StringBuilder();
-        update.append("update ").append(getTableName()).append(" set ");
-        for (int ii = 0; ii < modifiedFields.length; ii++) {
-            if (ii > 0) {
-                update.append(", ");
-            }
-            update.append(modifiedFields[ii]).append(" = ");
-            update.append(modifiedValues[ii]);
-        }
-        key.appendClause(null, update);
-
-        PreparedStatement pstmt = conn.prepareStatement(update.toString());
-        key.bindClauseArguments(pstmt, 1);
-        return pstmt;
-    }
 
     /**
      * This is called by the persistence context to register a migration for the entity managed by
@@ -652,47 +451,122 @@ public class DepotMarshaller<T extends PersistentRecord>
     protected void init (PersistenceContext ctx)
         throws PersistenceException
     {
+        SQLBuilder builder = ctx.getSQLBuilder(DepotTypes.TRIVIAL);
+
         if (_initialized) { // sanity check
             throw new IllegalStateException(
                 "Cannot re-initialize marshaller [type=" + _pclass + "].");
         }
         _initialized = true;
 
+        // perform the context-sensitive initialization of the field marshallers
+        for (FieldMarshaller fm : _fields.values()) {
+            fm.init(builder);
+        }
+
+        // figure out the list of fields that correspond to actual table columns and generate the
+        // SQL used to create and migrate our table (unless we're a computed entity)
+        _columnFields = new String[_allFields.length];
+        String[] declarations = new String[_allFields.length];
+        int jj = 0;
+        for (int ii = 0; ii < _allFields.length; ii++) {
+            @SuppressWarnings("unchecked") FieldMarshaller<T> fm = _fields.get(_allFields[ii]);
+            // include all persistent non-computed fields
+            String colDef = fm.getColumnDefinition();
+            if (colDef != null) {
+                _columnFields[jj] = _allFields[ii];
+                declarations[jj] = colDef;
+                jj ++;
+            }
+        }
+        _columnFields = ArrayUtil.splice(_columnFields, jj);
+        declarations = ArrayUtil.splice(declarations, jj);
+
         // if we have no table (i.e. we're a computed entity), we have nothing to create
         if (getTableName() == null) {
             return;
         }
 
+        // add any additional unique constraints
+        String[][] uniqueConstraintColumns = null;
+        Table table = _pclass.getAnnotation(Table.class);
+        if (table != null) {
+            UniqueConstraint[] uCons = table.uniqueConstraints();
+            uniqueConstraintColumns = new String[uCons.length][];
+            for (int kk = 0; kk < uCons.length; kk ++) {
+                String[] columns = uCons[kk].columnNames();
+                for (int ii = 0; ii < columns.length; ii ++) {
+                    FieldMarshaller fm = getFieldMarshaller(columns[ii]);
+                    if (fm == null) {
+                        throw new IllegalArgumentException(
+                            "Unknown field in @UniqueConstraint: " + columns[ii]);
+                    }
+                    columns[ii] = fm.getColumnName();
+                }
+                uniqueConstraintColumns[kk] = columns;
+            }
+        }
+
+        // if we did not find a schema version field, complain
+        if (_schemaVersion < 0) {
+            log.warning("Unable to read " + _pclass.getName() + "." + SCHEMA_VERSION_FIELD +
+                        ". Schema migration disabled.");
+        }
+
         // check to see if our schema version table exists, create it if not
         ctx.invoke(new Modifier() {
-            public int invoke (Connection conn) throws SQLException {
-                JDBCUtil.createTableIfMissing(
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                liaison.createTableIfMissing(
                     conn, SCHEMA_VERSION_TABLE,
-                    new String[] { "persistentClass VARCHAR(255) NOT NULL",
-                                   "version INTEGER NOT NULL" }, "");
+                    new String[] { "persistentClass", "version" },
+                    new String[] { "VARCHAR(255) NOT NULL", "INTEGER NOT NULL" },
+                    null,
+                    new String[] { "persistentClass" });
                 return 0;
             }
         });
 
         // now create the table for our persistent class if it does not exist
+        final String[] fDeclarations = declarations;
+        final String[][] fUniqueConstraintColumns = uniqueConstraintColumns;
         ctx.invoke(new Modifier() {
-            public int invoke (Connection conn) throws SQLException {
-                if (!JDBCUtil.tableExists(conn, getTableName())) {
-                    log.info("Creating table " + getTableName() + " (" + _declarations + ") " +
-                             _postamble);
-                    String[] definition = _declarations.toArray(new String[_declarations.size()]);
-                    JDBCUtil.createTableIfMissing(conn, getTableName(), definition, _postamble);
-                    updateVersion(conn, _schemaVersion);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                String[] columns = new String[_columnFields.length];
+                for (int ii = 0; ii < columns.length; ii ++) {
+                    columns[ii] = _fields.get(_columnFields[ii]).getColumnName();
                 }
+                String[] primaryKeyColumns = null;
+                if (_pkColumns != null) {
+                    primaryKeyColumns = new String[_pkColumns.size()];
+                    for (int ii = 0; ii < primaryKeyColumns.length; ii ++) {
+                        primaryKeyColumns[ii] = _pkColumns.get(ii).getColumnName();
+                    }
+                }
+                liaison.createTableIfMissing(conn, getTableName(), columns, fDeclarations,
+                                             fUniqueConstraintColumns, primaryKeyColumns);
+                updateVersion(conn, liaison, _schemaVersion);
                 return 0;
             }
         });
 
+        // ensure that all indices are created
+        final Entity entity = _pclass.getAnnotation(Entity.class);
+        if (entity != null && entity.indices().length > 0) {
+            ctx.invoke(new Modifier() {
+                public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                    for (Index idx : entity.indices()) {
+                        liaison.addIndexToTable(conn, getTableName(), idx.columns(), idx.name());
+                    }
+                    return entity.indices().length;
+                }
+            });
+        }
+
         // if we have a key generator, initialize that too
         if (_keyGenerator != null) {
             ctx.invoke(new Modifier() {
-                public int invoke (Connection conn) throws SQLException {
-                    _keyGenerator.init(conn);
+                public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                    _keyGenerator.init(conn, liaison);
                     return 0;
                 }
             });
@@ -706,9 +580,12 @@ public class DepotMarshaller<T extends PersistentRecord>
 
         // make sure the versions match
         int currentVersion = ctx.invoke(new Modifier() {
-            public int invoke (Connection conn) throws SQLException {
-                String query = "select version from " + SCHEMA_VERSION_TABLE +
-                    " where persistentClass = '" + getTableName() + "'";
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                String query =
+                    " select " + liaison.columnSQL("version") +
+                    "   from " + liaison.tableSQL(SCHEMA_VERSION_TABLE) +
+                    "  where " + liaison.columnSQL("persistentClass") +
+                    " = '" + getTableName() + "'";
                 Statement stmt = conn.createStatement();
                 try {
                     ResultSet rs = stmt.executeQuery(query);
@@ -723,6 +600,12 @@ public class DepotMarshaller<T extends PersistentRecord>
             return;
         }
 
+        if (true) {
+            log.warning("Automatic schema migration is temporarily disabled.");
+            verifySchemasMatch(ctx);
+            return;
+        }
+
         // otherwise try to migrate the schema
         log.info("Migrating " + getTableName() + " from " +
                  currentVersion + " to " + _schemaVersion + "...");
@@ -736,35 +619,29 @@ public class DepotMarshaller<T extends PersistentRecord>
             }
         }
 
-        // enumerate all of the columns now that we've run our pre-migrations
-        Set<String> columns = new HashSet<String>();
-        Map<String, Set<String>> indexColumns = new HashMap<String, Set<String>>();
-        loadMetaData(ctx, columns, indexColumns);
+        // enumerate all columns and indexes now that we've run our pre-migrations
+        TableMetaData metaData = loadMetaData(ctx);
 
         // this is a little silly, but we need a copy for name disambiguation later
-        Set<String> indicesCopy = new HashSet<String>(indexColumns.keySet());
+        Set<String> indicesCopy = new HashSet<String>(metaData.indexColumns.keySet());
 
         // add any missing columns
         for (String fname : _columnFields) {
-            FieldMarshaller fmarsh = _fields.get(fname);
-            if (columns.remove(fmarsh.getColumnName())) {
+            @SuppressWarnings("unchecked") final FieldMarshaller<T> fmarsh = _fields.get(fname);
+            if (metaData.tableColumns.remove(fmarsh.getColumnName())) {
                 continue;
             }
 
             // otherwise add the column
-            String coldef = fmarsh.getColumnDefinition();
-            String query = "alter table " + getTableName() + " add column " + coldef;
-
-            // try to add it to the appropriate spot
-            int fidx = ListUtil.indexOf(_allFields, fmarsh.getColumnName());
-            if (fidx == 0) {
-                query += " first";
-            } else {
-                query += " after " + _allFields[fidx-1];
+            final String coldef = fmarsh.getColumnDefinition();
+            log.info("Adding column to " + getTableName() + ": " +
+                     fmarsh.getColumnName() + " " + coldef);
+            ctx.invoke(new Modifier.Simple() {
+                protected String createQuery (DatabaseLiaison liaison) {
+                    return "alter table " + liaison.tableSQL(getTableName()) +
+                        " add column " + liaison.columnSQL(fmarsh.getColumnName()) + " " + coldef;
                 }
-
-            log.info("Adding column to " + getTableName() + ": " + coldef);
-            ctx.invoke(new Modifier.Simple(query));
+            });
 
             // if the column is a TIMESTAMP or DATETIME column, we need to run a special query to
             // update all existing rows to the current time because MySQL annoyingly assigns
@@ -773,75 +650,84 @@ public class DepotMarshaller<T extends PersistentRecord>
             // cannot accept CURRENT_TIME or NOW() defaults at all.
             if (coldef.toLowerCase().indexOf(" timestamp") != -1 ||
                 coldef.toLowerCase().indexOf(" datetime") != -1) {
-                query = "update " + getTableName() + " set " + fmarsh.getColumnName() + " = NOW()";
-                log.info("Assigning current time to column: " + query);
-                ctx.invoke(new Modifier.Simple(query));
+                log.info("Assigning current time to " + fmarsh.getColumnName() + ".");
+                ctx.invoke(new Modifier.Simple() {
+                    protected String createQuery (DatabaseLiaison liaison) {
+                        // TODO: is NOW() standard SQL?
+                        return "update " + liaison.tableSQL(getTableName()) +
+                            " set " + liaison.columnSQL(fmarsh.getColumnName()) + " = NOW()";
+                    }
+                });
             }
         }
 
-        // add or remove the primary key as needed
-        if (hasPrimaryKey() && !indexColumns.containsKey("PRIMARY")) {
-            String pkdef = "primary key (" + getJoinedKeyColumns() + ")";
-            log.info("Adding primary key to " + getTableName() + ": " + pkdef);
-            ctx.invoke(new Modifier.Simple("alter table " + getTableName() + " add " + pkdef));
+        // TODO: This needs more work to be database-independent, I think. Assuming the index name
+        // is going to be PRIMARY seems like a MySQL-ism, and we'll do the rest of the index work
+        // when we do that.
 
-        } else if (!hasPrimaryKey() && indexColumns.containsKey("PRIMARY")) {
-            indexColumns.remove("PRIMARY");
-            log.info("Dropping primary from " + getTableName());
-            ctx.invoke(new Modifier.Simple("alter table " + getTableName() + " drop primary key"));
-        }
-
-        // add any missing indices
-        Entity entity = _pclass.getAnnotation(Entity.class);
-        for (Index index : (entity == null ? new Index[0] : entity.indices())) {
-            if (indexColumns.containsKey(index.name())) {
-                indexColumns.remove(index.name());
-                continue;
-            }
-            String indexdef = "create " + index.type() + " index " + index.name() +
-                " on " + getTableName() + " (" + StringUtil.join(index.columns(), ", ") + ")";
-            log.info("Adding index: " + indexdef);
-            ctx.invoke(new Modifier.Simple(indexdef));
-        }
-
-        // to get the @Table(uniqueIndices...) indices, we use our clever set of column name sets
-        Set<Set<String>> uniqueIndices = new HashSet<Set<String>>(indexColumns.values());
-        Table table;
-        if (getTableName() != null && (table = _pclass.getAnnotation(Table.class)) != null) {
-            Set<String> colSet = new HashSet<String>();
-            for (UniqueConstraint constraint : table.uniqueConstraints()) {
-                // for each given UniqueConstraint, build a new column set
-                colSet.clear();
-                for (String column : constraint.columnNames()) {
-                    colSet.add(column);
-                }
-                // and check if the table contained this set
-                if (uniqueIndices.contains(colSet)) {
-                    continue; // good, carry on
-                }
-
-                // else build the index; we'll use mysql's convention of naming it after a column,
-                // with possible _N disambiguation; luckily we made a copy of the index names!
-                String indexName = colSet.iterator().next();
-                if (indicesCopy.contains(indexName)) {
-                    int num = 1;
-                    indexName += "_";
-                    while (indicesCopy.contains(indexName + num)) {
-                        num ++;
-                    }
-                    indexName += num;
-                }
-
-                String[] columnArr = colSet.toArray(new String[colSet.size()]);
-                String indexdef = "create unique index " + indexName + " on " +
-                    getTableName() + " (" + StringUtil.join(columnArr, ", ") + ")";
-                log.info("Adding unique index: " + indexdef);
-                ctx.invoke(new Modifier.Simple(indexdef));
-            }
-        }
+//        // add or remove the primary key as needed
+//        if (hasPrimaryKey() && !indexColumns.containsKey("PRIMARY")) {
+//            String pkdef = "primary key (" + getJoinedKeyColumns() + ")";
+//            log.info("Adding primary key to " + getTableName() + ": " + pkdef);
+//            ctx.invoke(new Modifier.Simple("alter table " + getTableName() + " add " + pkdef));
+//
+//        } else if (!hasPrimaryKey() && indexColumns.containsKey("PRIMARY")) {
+//            indexColumns.remove("PRIMARY");
+//            log.info("Dropping primary from " + getTableName());
+//            ctx.invoke(new Modifier.Simple("alter table " + getTableName() + " drop primary key"));
+//        }
+//
+//        // add any missing indices
+//        for (Index index : (entity == null ? new Index[0] : entity.indices())) {
+//            if (indexColumns.containsKey(index.name())) {
+//                indexColumns.remove(index.name());
+//                continue;
+//            }
+//            String indexdef =
+//                "create " + index.type() + " index " + _liaison.indexSQL(index.name()) +
+//                " on " + _liaison.tableSQL(getTableName()) + " (" + StringUtil.join(index.columns(), ", ") + ")";
+//            log.info("Adding index: " + indexdef);
+//            ctx.invoke(new Modifier.Simple(indexdef));
+//        }
+//
+//        // to get the @Table(uniqueIndices...) indices, we use our clever set of column name sets
+//        Set<Set<String>> uniqueIndices = new HashSet<Set<String>>(indexColumns.values());
+//        Table table;
+//        if (getTableName() != null && (table = _pclass.getAnnotation(Table.class)) != null) {
+//            Set<String> colSet = new HashSet<String>();
+//            for (UniqueConstraint constraint : table.uniqueConstraints()) {
+//                // for each given UniqueConstraint, build a new column set
+//                colSet.clear();
+//                for (String column : constraint.columnNames()) {
+//                    colSet.add(column);
+//                }
+//                // and check if the table contained this set
+//                if (uniqueIndices.contains(colSet)) {
+//                    continue; // good, carry on
+//                }
+//
+//                // else build the index; we'll use mysql's convention of naming it after a column,
+//                // with possible _N disambiguation; luckily we made a copy of the index names!
+//                String indexName = colSet.iterator().next();
+//                if (indicesCopy.contains(indexName)) {
+//                    int num = 1;
+//                    indexName += "_";
+//                    while (indicesCopy.contains(indexName + num)) {
+//                        num ++;
+//                    }
+//                    indexName += num;
+//                }
+//
+//                String[] columnArr = colSet.toArray(new String[colSet.size()]);
+//                String indexdef = "create unique index " + indexName + " on " +
+//                    getTableName() + " (" + StringUtil.join(columnArr, ", ") + ")";
+//                log.info("Adding unique index: " + indexdef);
+//                ctx.invoke(new Modifier.Simple(indexdef));
+//            }
+//        }
 
         // we do not auto-remove columns but rather require that EntityMigration.Drop records be
-        // registered by hand to avoid accidentally causin the loss of data
+        // registered by hand to avoid accidentally causing the loss of data
 
         // we don't auto-remove indices either because we'd have to sort out the potentially
         // complex origins of an index (which might be because of a @Unique column or maybe the
@@ -858,29 +744,39 @@ public class DepotMarshaller<T extends PersistentRecord>
 
         // record our new version in the database
         ctx.invoke(new Modifier() {
-            public int invoke (Connection conn) throws SQLException {
-                updateVersion(conn, _schemaVersion);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                updateVersion(conn, liaison, _schemaVersion);
                 return 0;
             }
         });
     }
 
-    /**
-     * Loads up the metadata for our database table: the names of our columns and indices.
-     */
-    protected void loadMetaData (PersistenceContext ctx, final Set<String> columns,
-                                 final Map<String, Set<String>> indexColumns)
+    protected TableMetaData loadMetaData (PersistenceContext ctx)
         throws PersistenceException
     {
-        ctx.invoke(new Modifier() {
-            public int invoke (Connection conn) throws SQLException {
-                DatabaseMetaData meta = conn.getMetaData();
-                ResultSet rs = meta.getColumns(null, null, getTableName(), "%");
-                while (rs.next()) {
-                    columns.add(rs.getString("COLUMN_NAME"));
+        return ctx.invoke(new Query.TrivialQuery<TableMetaData>() {
+            public TableMetaData invoke (Connection conn, DatabaseLiaison liaison)
+                throws SQLException {
+                return new TableMetaData(conn.getMetaData());
+            }
+        });
+    }
+
+    protected class TableMetaData
+    {
+        public Set<String> tableColumns = new HashSet<String>();
+        public Map<String, Set<String>> indexColumns = new HashMap<String, Set<String>>();
+        public String pkName;
+        public Set<String> pkColumns = new HashSet<String>();
+
+        public TableMetaData (DatabaseMetaData meta)
+            throws SQLException
+        {
+            ResultSet rs = meta.getColumns(null, null, getTableName(), "%");
+            while (rs.next()) {
+                tableColumns.add(rs.getString("COLUMN_NAME"));
             }
 
-                if (indexColumns != null) {
             rs = meta.getIndexInfo(null, null, getTableName(), false, false);
             while (rs.next()) {
                 String indexName = rs.getString("INDEX_NAME");
@@ -900,11 +796,13 @@ public class DepotMarshaller<T extends PersistentRecord>
                     set.add(rs.getString("COLUMN_NAME"));
                 }
             }
-                }
 
-                return 0;
+            rs = meta.getPrimaryKeys(null, null, getTableName());
+            while (rs.next()) {
+                pkName = rs.getString("PK_NAME");
+                pkColumns.add(rs.getString("COLUMN_NAME"));
+            }
         }
-        });
     }
 
     /**
@@ -913,32 +811,29 @@ public class DepotMarshaller<T extends PersistentRecord>
     protected void verifySchemasMatch (PersistenceContext ctx)
         throws PersistenceException
     {
-        Set<String> columns = new HashSet<String>();
-        loadMetaData(ctx, columns, null);
+        TableMetaData meta = loadMetaData(ctx);
         for (String fname : _columnFields) {
             FieldMarshaller fmarsh = _fields.get(fname);
-            columns.remove(fmarsh.getColumnName());
+            meta.tableColumns.remove(fmarsh.getColumnName());
         }
-        for (String column : columns) {
+        for (String column : meta.tableColumns) {
             log.warning(getTableName() + " contains stale column '" + column + "'.");
         }
     }
 
-    protected String getJoinedKeyColumns ()
-    {
-        return StringUtil.join(getPrimaryKeyColumns(), ", ");
-    }
-
-    protected void updateVersion (Connection conn, int version)
+    protected void updateVersion (Connection conn, DatabaseLiaison liaison, int version)
         throws SQLException
     {
-        String update = "update " + SCHEMA_VERSION_TABLE +
-            " set version = " + version + " where persistentClass = '" + getTableName() + "'";
-        String insert = "insert into " + SCHEMA_VERSION_TABLE +
-            " values('" + getTableName() + "', " + version + ")";
+        String update =
+            "update " + liaison.tableSQL(SCHEMA_VERSION_TABLE) +
+            "   set " + liaison.columnSQL("version") + " = " + version +
+            " where " + liaison.columnSQL("persistentClass") + " = '" + getTableName() + "'";
         Statement stmt = conn.createStatement();
         try {
             if (stmt.executeUpdate(update) == 0) {
+                String insert =
+                    "insert into " + liaison.tableSQL(SCHEMA_VERSION_TABLE) +
+                    " values('" + getTableName() + "', " + version + ")";
                 stmt.executeUpdate(insert);
             }
         } finally {
@@ -946,15 +841,6 @@ public class DepotMarshaller<T extends PersistentRecord>
         }
     }
 
-    protected void requireNotComputed (String action)
-        throws SQLException
-    {
-        if (getTableName() == null) {
-            throw new IllegalArgumentException(
-                "Can't " + action + " computed entities [class=" + _pclass + "]");
-        }
-    }
-
     /** The persistent object class that we manage. */
     protected Class<T> _pclass;
 
@@ -962,10 +848,10 @@ public class DepotMarshaller<T extends PersistentRecord>
     protected String _tableName;
 
     /** A field marshaller for each persistent field in our object. */
-    protected HashMap<String, FieldMarshaller> _fields = new HashMap<String, FieldMarshaller>();
+    protected Map<String, FieldMarshaller> _fields = new HashMap<String, FieldMarshaller>();
 
-    /** The field marshallers for our persistent object's primary key columns
-     * or null if it did not define a primary key. */
+    /** The field marshallers for our persistent object's primary key columns or null if it did not
+     * define a primary key. */
     protected ArrayList<FieldMarshaller> _pkColumns;
 
     /** The generator to use for auto-generating primary key values, or null. */
@@ -977,16 +863,9 @@ public class DepotMarshaller<T extends PersistentRecord>
     /** The fields of our object with directly corresponding table columns. */
     protected String[] _columnFields;
 
-    /** The version of our persistent object schema as specified in the class
-     * definition. */
+    /** The version of our persistent object schema as specified in the class definition. */
     protected int _schemaVersion = -1;
 
-    /** Used when creating and migrating our table schema. */
-    protected ArrayList<String> _declarations = new ArrayList<String>();
-
-    /** Used when creating and migrating our table schema. */
-    protected String _postamble = "";
-
     /** Indicates that we have been initialized (created or migrated our tables). */
     protected boolean _initialized;
 

src/java/com/samskivert/jdbc/depot/DepotRepository.java

@@ -29,15 +29,22 @@ import java.util.List;
 import java.util.Map;
 
 import com.samskivert.io.PersistenceException;
+import com.samskivert.util.ArrayUtil;
+
 import com.samskivert.jdbc.ConnectionProvider;
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.jdbc.JDBCUtil;
+
 import com.samskivert.jdbc.depot.Modifier.*;
+import com.samskivert.jdbc.depot.clause.DeleteClause;
 import com.samskivert.jdbc.depot.clause.FieldOverride;
 import com.samskivert.jdbc.depot.clause.FromOverride;
+import com.samskivert.jdbc.depot.clause.InsertClause;
 import com.samskivert.jdbc.depot.clause.Join;
 import com.samskivert.jdbc.depot.clause.QueryClause;
-import com.samskivert.jdbc.depot.clause.Where;
-import com.samskivert.util.ArrayUtil;
+import com.samskivert.jdbc.depot.clause.UpdateClause;
+import com.samskivert.jdbc.depot.expression.SQLExpression;
+import com.samskivert.jdbc.depot.expression.ValueExp;
 
 /**
  * Provides a base for classes that provide access to persistent objects. Also defines the
@@ -163,18 +170,36 @@ public class DepotRepository
     protected <T extends PersistentRecord> int insert (T record)
         throws PersistenceException
     {
-        final DepotMarshaller marsh = _ctx.getMarshaller(record.getClass());
-        final Key key = marsh.getPrimaryKey(record, false);
+        @SuppressWarnings("unchecked") final Class<T> pClass = (Class<T>) record.getClass();
+        final DepotMarshaller<T> marsh = _ctx.getMarshaller(pClass);
+        Key<T> key = marsh.getPrimaryKey(record, false);
+
+        DepotTypes types = DepotTypes.getDepotTypes(_ctx);
+        types.addClass(_ctx, pClass);
+        final SQLBuilder builder = _ctx.getSQLBuilder(types);
+
         // key will be null if record was supplied without a primary key
         return _ctx.invoke(new CachingModifier<T>(record, key, key) {
-            public int invoke (Connection conn) throws SQLException {
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
                 // update our modifier's key so that it can cache our results
-                updateKey(marsh.assignPrimaryKey(conn, _result, false));
-                PreparedStatement stmt = marsh.createInsert(conn, _result);
+                if (_key == null) {
+                    updateKey(marsh.assignPrimaryKey(conn, liaison, _result, false));
+                }
+
+                String ixField = null;
+                if (_key == null && marsh.hasPrimaryKey() && marsh.getKeyGenerator() != null &&
+                        marsh.getKeyGenerator() instanceof IdentityKeyGenerator) {
+                    ixField = ((IdentityKeyGenerator) marsh.getKeyGenerator()).getColumn();
+                }
+                builder.newQuery(new InsertClause<T>(pClass, _result, ixField));
+
+                PreparedStatement stmt = builder.prepare(conn);
                 try {
                     int mods = stmt.executeUpdate();
                     // check again in case we have a post-factum key generator
-                    updateKey(marsh.assignPrimaryKey(conn, _result, true));
+                    if (_key == null) {
+                        updateKey(marsh.assignPrimaryKey(conn, liaison, _result, true));
+                    }
                     return mods;
                 } finally {
                     JDBCUtil.close(stmt);
@@ -192,14 +217,22 @@ public class DepotRepository
     protected <T extends PersistentRecord> int update (T record)
         throws PersistenceException
     {
-        final DepotMarshaller marsh = _ctx.getMarshaller(record.getClass());
-        final Key key = marsh.getPrimaryKey(record);
+        @SuppressWarnings("unchecked") Class<T> pClass = (Class<T>) record.getClass();
+        requireNotComputed(pClass, "update");
+
+        DepotMarshaller<T> marsh = _ctx.getMarshaller(pClass);
+        Key key = marsh.getPrimaryKey(record);
         if (key == null) {
             throw new IllegalArgumentException("Can't update record with null primary key.");
         }
+
+        UpdateClause<T> update = new UpdateClause<T>(pClass, key, marsh._columnFields, record);
+        final SQLBuilder builder = _ctx.getSQLBuilder(DepotTypes.getDepotTypes(_ctx, update));
+        builder.newQuery(update);
+
         return _ctx.invoke(new CachingModifier<T>(record, key, key) {
-            public int invoke (Connection conn) throws SQLException {
-                PreparedStatement stmt = marsh.createUpdate(conn, _result, key);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                PreparedStatement stmt = builder.prepare(conn);
                 try {
                     return stmt.executeUpdate();
                 } finally {
@@ -220,14 +253,26 @@ public class DepotRepository
     protected <T extends PersistentRecord> int update (T record, final String... modifiedFields)
         throws PersistenceException
     {
-        final DepotMarshaller marsh = _ctx.getMarshaller(record.getClass());
-        final Key key = marsh.getPrimaryKey(record);
+        @SuppressWarnings("unchecked")
+        Class<T> pClass = (Class<T>) record.getClass();
+
+        requireNotComputed(pClass, "updatePartial");
+
+        DepotMarshaller<T> marsh = _ctx.getMarshaller(pClass);
+        Key key = marsh.getPrimaryKey(record);
+
         if (key == null) {
             throw new IllegalArgumentException("Can't update record with null primary key.");
         }
+
+        UpdateClause<T> update = new UpdateClause<T>(pClass, key, modifiedFields, record);
+
+        final SQLBuilder builder = _ctx.getSQLBuilder(DepotTypes.getDepotTypes(_ctx, update));
+        builder.newQuery(update);
+
         return _ctx.invoke(new CachingModifier<T>(record, key, key) {
-            public int invoke (Connection conn) throws SQLException {
-                PreparedStatement stmt = marsh.createUpdate(conn, _result, key, modifiedFields);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                PreparedStatement stmt = builder.prepare(conn);
                 // clear out _result so that we don't rewrite this partial record to the cache
                 _result = null;
                 try {
@@ -336,21 +381,23 @@ public class DepotRepository
      * @return the number of rows modified by this action.
      */
     protected <T extends PersistentRecord> int updatePartial (
-        Class<T> type, final Where key, CacheInvalidator invalidator, Object... fieldsValues)
+        Class<T> type, final WhereClause key, CacheInvalidator invalidator, Object... fieldsValues)
         throws PersistenceException
     {
         // separate the arguments into keys and values
         final String[] fields = new String[fieldsValues.length/2];
-        final Object[] values = new Object[fields.length];
+        final SQLExpression[] values = new SQLExpression[fields.length];
         for (int ii = 0, idx = 0; ii < fields.length; ii++) {
             fields[ii] = (String)fieldsValues[idx++];
-            values[ii] = fieldsValues[idx++];
+            values[ii] = new ValueExp(fieldsValues[idx++]);
         }
+        UpdateClause<T> update = new UpdateClause<T>(type, key, fields, values);
+        final SQLBuilder builder = _ctx.getSQLBuilder(DepotTypes.getDepotTypes(_ctx, update));
+        builder.newQuery(update);
 
-        final DepotMarshaller marsh = _ctx.getMarshaller(type);
         return _ctx.invoke(new Modifier(invalidator) {
-            public int invoke (Connection conn) throws SQLException {
-                PreparedStatement stmt = marsh.createPartialUpdate(conn, key, fields, values);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                PreparedStatement stmt = builder.prepare(conn);
                 try {
                     return stmt.executeUpdate();
                 } finally {
@@ -378,11 +425,11 @@ public class DepotRepository
      * @return the number of rows modified by this action.
      */
     protected <T extends PersistentRecord> int updateLiteral (
-        Class<T> type, Comparable primaryKey, String... fieldsValues)
+        Class<T> type, Comparable primaryKey, Map<String, SQLExpression> fieldsToValues)
         throws PersistenceException
     {
         Key<T> key = _ctx.getMarshaller(type).makePrimaryKey(primaryKey);
-        return updateLiteral(type, key, key, fieldsValues);
+        return updateLiteral(type, key, key, fieldsToValues);
     }
 
     /**
@@ -404,11 +451,11 @@ public class DepotRepository
      */
     protected <T extends PersistentRecord> int updateLiteral (
         Class<T> type, String ix1, Comparable val1, String ix2, Comparable val2,
-        String... fieldsValues)
+        Map<String, SQLExpression> fieldsToValues)
         throws PersistenceException
     {
         Key<T> key = new Key<T>(type, ix1, val1, ix2, val2);
-        return updateLiteral(type, key, key, fieldsValues);
+        return updateLiteral(type, key, key, fieldsToValues);
     }
 
     /**
@@ -430,11 +477,11 @@ public class DepotRepository
      */
     protected <T extends PersistentRecord> int updateLiteral (
         Class<T> type, String ix1, Comparable val1, String ix2, Comparable val2,
-        String ix3, Comparable val3, String... fieldsValues)
+        String ix3, Comparable val3, Map<String, SQLExpression> fieldsToValues)
         throws PersistenceException
     {
         Key<T> key = new Key<T>(type, ix1, val1, ix2, val2, ix3, val3);
-        return updateLiteral(type, key, key, fieldsValues);
+        return updateLiteral(type, key, key, fieldsToValues);
     }
 
     /**
@@ -455,21 +502,29 @@ public class DepotRepository
      * @return the number of rows modified by this action.
      */
     protected <T extends PersistentRecord> int updateLiteral (
-        Class<T> type, final Where key, CacheInvalidator invalidator, String... fieldsValues)
+        Class<T> type, final WhereClause key, CacheInvalidator invalidator,
+        Map<String, SQLExpression> fieldsToValues)
         throws PersistenceException
     {
+        requireNotComputed(type, "updateLiteral");
+
         // separate the arguments into keys and values
-        final String[] fields = new String[fieldsValues.length/2];
-        final String[] values = new String[fields.length];
-        for (int ii = 0, idx = 0; ii < fields.length; ii++) {
-            fields[ii] = fieldsValues[idx++];
-            values[ii] = fieldsValues[idx++];
+        final String[] fields = new String[fieldsToValues.size()];
+        final SQLExpression[] values = new SQLExpression[fields.length];
+        int ii = 0;
+        for (Map.Entry<String, SQLExpression> entry : fieldsToValues.entrySet()) {
+            fields[ii] = entry.getKey();
+            values[ii] = entry.getValue();
+            ii ++;
         }
 
-        final DepotMarshaller marsh = _ctx.getMarshaller(type);
+        UpdateClause<T> update = new UpdateClause<T>(type, key, fields, values);
+        final SQLBuilder builder = _ctx.getSQLBuilder(DepotTypes.getDepotTypes(_ctx, update));
+        builder.newQuery(update);
+
         return _ctx.invoke(new Modifier(invalidator) {
-            public int invoke (Connection conn) throws SQLException {
-                PreparedStatement stmt = marsh.createLiteralUpdate(conn, key, fields, values);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                PreparedStatement stmt = builder.prepare(conn);
                 try {
                     return stmt.executeUpdate();
                 } finally {
@@ -489,17 +544,25 @@ public class DepotRepository
     protected <T extends PersistentRecord> boolean store (T record)
         throws PersistenceException
     {
-        final DepotMarshaller marsh = _ctx.getMarshaller(record.getClass());
-        final Key key = marsh.hasPrimaryKey() ? marsh.getPrimaryKey(record) : null;
+        @SuppressWarnings("unchecked") final Class<T> pClass = (Class<T>) record.getClass();
+        requireNotComputed(pClass, "store");
+
+        final DepotMarshaller<T> marsh = _ctx.getMarshaller(pClass);
+        Key<T> key = marsh.hasPrimaryKey() ? marsh.getPrimaryKey(record) : null;
+        final UpdateClause<T> update =
+            new UpdateClause<T>(pClass, key, marsh._columnFields, record);
+        final SQLBuilder builder = _ctx.getSQLBuilder(DepotTypes.getDepotTypes(_ctx, update));
+        builder.newQuery(update);
+
         final boolean[] created = new boolean[1];
         _ctx.invoke(new CachingModifier<T>(record, key, key) {
-            public int invoke (Connection conn) throws SQLException {
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
                 PreparedStatement stmt = null;
                 try {
-                    // if our primary key isn't null, update rather than insert the record
-                    // before been persisted and insert
-                    if (key != null) {
-                        stmt = marsh.createUpdate(conn, _result, key);
+                    // if our primary key isn't null, update rather than insert the record before
+                    // been persisted and insert
+                    if (_key != null) {
+                        stmt = builder.prepare(conn);
                         int mods = stmt.executeUpdate();
                         if (mods > 0) {
                             return mods;
@@ -509,10 +572,22 @@ public class DepotRepository
 
                     // if the update modified zero rows or the primary key was obviously unset, do
                     // an insertion
-                    updateKey(marsh.assignPrimaryKey(conn, _result, false));
-                    stmt = marsh.createInsert(conn, _result);
+                    if (_key == null) {
+                        updateKey(marsh.assignPrimaryKey(conn, liaison, _result, false));
+                    }
+
+                    String ixField = null;
+                    if (_key == null && marsh.hasPrimaryKey() && marsh.getKeyGenerator() != null &&
+                            marsh.getKeyGenerator() instanceof IdentityKeyGenerator) {
+                        ixField = ((IdentityKeyGenerator) marsh.getKeyGenerator()).getColumn();
+                    }
+                    builder.newQuery(new InsertClause<T>(pClass, _result, ixField));
+
+                    stmt = builder.prepare(conn);
                     int mods = stmt.executeUpdate();
-                    updateKey(marsh.assignPrimaryKey(conn, _result, true));
+                    if (_key == null) {
+                        updateKey(marsh.assignPrimaryKey(conn, liaison, _result, true));
+                    }
                     created[0] = true;
                     return mods;
 
@@ -571,13 +646,16 @@ public class DepotRepository
      * @return the number of rows deleted by this action.
      */
     protected <T extends PersistentRecord> int deleteAll (
-        Class<T> type, final Where key, CacheInvalidator invalidator)
+        Class<T> type, final WhereClause key, CacheInvalidator invalidator)
         throws PersistenceException
     {
-        final DepotMarshaller marsh = _ctx.getMarshaller(type);
+        DeleteClause<T> delete = new DeleteClause<T>(type, key);
+        final SQLBuilder builder = _ctx.getSQLBuilder(DepotTypes.getDepotTypes(_ctx, delete));
+        builder.newQuery(delete);
+
         return _ctx.invoke(new Modifier(invalidator) {
-            public int invoke (Connection conn) throws SQLException {
-                PreparedStatement stmt = marsh.createDelete(conn, key);
+            public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+                PreparedStatement stmt = builder.prepare(conn);
                 try {
                     return stmt.executeUpdate();
                 } finally {
@@ -587,25 +665,18 @@ public class DepotRepository
         });
     }
 
-    protected static abstract class CollectionQuery<T extends Collection> implements Query<T>
-    {
-        public CollectionQuery (CacheKey key)
+    // make sure the given type corresponds to a concrete class
+    protected void requireNotComputed (Class<? extends PersistentRecord> type, String action)
         throws PersistenceException
     {
-            _key = key;
+        DepotMarshaller marsh = _ctx.getMarshaller(type);
+        if (marsh == null) {
+            throw new PersistenceException("Unknown persistent type [class=" + type + "]");
         }
-
-        public CacheKey getCacheKey ()
-        {
-            return _key;
+        if (marsh.getTableName() == null) {
+            throw new PersistenceException(
+                "Can't " + action + " computed entities [class=" + type + "]");
         }
-
-        public void updateCache (PersistenceContext ctx, T result)
-        {
-            ctx.cacheStore(_key, result);
-        }
-
-        protected CacheKey _key;
     }
 
     protected PersistenceContext _ctx;

src/java/com/samskivert/jdbc/depot/DepotTypes.java

@@ -20,52 +20,60 @@
 
 package com.samskivert.jdbc.depot;
 
+import java.sql.SQLException;
+
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
 import com.samskivert.io.PersistenceException;
+import com.samskivert.jdbc.depot.clause.QueryClause;
+import com.samskivert.jdbc.depot.expression.SQLExpression;
 
 /**
- * Primarily an implementation of {@link QueryBuilderContext}, this class holds the persistent
- * classes used in the context of a single query and maps them to {@link DepotMarshaller}
- * instances as well as table names and table abbreviations.
+ * Maintains a record of the persistent classes brought into the context of the associated SQL,
+ * i.e. any class associated with a concrete table that would appear in FROM or JOIN clauses or as
+ * the target of an UPDATE or an INSERT or any other place where a table abbreviation could be
+ * constructed.
  *
- * The main motivation for breaking this functionality out into its own class is to encapsulate
- * the operation that throws {@link PersistenceException} as separate from the operations that
- * throw {@link SQLException}.
+ * The main motivation for breaking this functionality out into its own class is to encapsulate the
+ * operation that throws {@link PersistenceException} as separate from the operations that throw
+ * {@link SQLException}. Once this class has been constructed, it may be used to create {@link
+ * SQLBuilder} instances without any {@link PersistenceException} worries.
  */
-public class DepotTypes<T>
-    implements QueryBuilderContext<T>
+public class DepotTypes
 {
-    public DepotTypes (PersistenceContext ctx,
-                       Class<? extends PersistentRecord> main,
-                       Set<Class<? extends PersistentRecord>> others)
+    /** A trivial instance that is accessible in places where we want the dialectal benefits of the
+     * SQLBuilder without really requiring per-persistent-class context. */
+    public static DepotTypes TRIVIAL = new DepotTypes();
+
+    /**
+     * Conveniently constructs a {@link DepotTypes} object given {@link QueryClause} objects, which
+     * are interrogated for their class definition sets through {@link SQLExpression#addClasses}.
+     */
+    public static <T extends PersistentRecord> DepotTypes getDepotTypes (
+        PersistenceContext ctx, QueryClause... clauses)
         throws PersistenceException
     {
-        _mainType = main;
-        _classMap = new HashMap<Class, DepotMarshaller>();
-
-        for (Class<? extends PersistentRecord> c : others) {
-            _classMap.put(c, ctx.getMarshaller(c));
+        Set<Class<? extends PersistentRecord>> classSet =
+            new HashSet<Class<? extends PersistentRecord>>();
+        for (QueryClause clause : clauses) {
+            if (clause != null) {
+                clause.addClasses(classSet);
             }
-        _classList = new ArrayList<Class<? extends PersistentRecord>>(others);
+        }
+        return new DepotTypes(ctx, classSet);
     }
 
-    public Class<? extends PersistentRecord> getMainType ()
-    {
-        return _mainType;
-    }
-
-    // from ConstructedQuery
     public String getTableName (Class<? extends PersistentRecord> cl)
     {
         return _classMap.get(cl).getTableName();
     }
 
-    // from ConstructedQuery
     public String getTableAbbreviation (Class<? extends PersistentRecord> cl)
     {
         int ix = _classList.indexOf(cl);
@@ -75,32 +83,42 @@ public class DepotTypes<T>
         return "T" + (ix+1);
     }
 
+    public String getColumnName (Class<? extends PersistentRecord> cl, String field)
+    {
+        return getMarshaller(cl).getFieldMarshaller(field).getColumnName();
+    }
+
     public DepotMarshaller getMarshaller (Class cl)
     {
         return _classMap.get(cl);
     }
 
-    public String getMainTableName ()
+    public void addClass (PersistenceContext ctx, Class <? extends PersistentRecord> type)
+        throws PersistenceException
     {
-        return getTableName(_mainType);
+        if (_classMap.containsKey(type)) {
+            return;
+        }
+        _classList.add(type);
+        _classMap.put(type, ctx.getMarshaller(type));
     }
 
-    public DepotMarshaller getMainMarshaller ()
+    protected DepotTypes (PersistenceContext ctx, Set<Class<? extends PersistentRecord>> others)
+        throws PersistenceException
     {
-        return getMarshaller(_mainType);
+        for (Class<? extends PersistentRecord> c : others) {
+            addClass(ctx, c);
+        }
     }
 
-    public String getMainTableAbbreviation ()
+    protected DepotTypes ()
     {
-        return getTableAbbreviation(_mainType);
     }
 
-    /** The persistent class to instantiate for the results. */
-    protected Class<? extends PersistentRecord> _mainType;
-
     /** A list of referenced classes, used to generate table abbreviations. */
-    protected List<Class<? extends PersistentRecord>> _classList;
+    protected List<Class<? extends PersistentRecord>> _classList =
+        new ArrayList<Class<? extends PersistentRecord>>();
 
     /** Classes mapped to marshallers, used for table names and field lists. */
-    protected Map<Class, DepotMarshaller> _classMap;
+    protected Map<Class, DepotMarshaller> _classMap = new HashMap<Class, DepotMarshaller>();
 }

src/java/com/samskivert/jdbc/depot/EntityMigration.java

@@ -22,10 +22,11 @@ package com.samskivert.jdbc.depot;
 
 import java.sql.Connection;
 import java.sql.SQLException;
-import java.sql.Statement;
-import java.util.HashMap;
+import java.util.Map;
 
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.jdbc.JDBCUtil;
+import com.samskivert.jdbc.LiaisonRegistry;
 
 import static com.samskivert.jdbc.depot.Log.log;
 
@@ -47,21 +48,15 @@ public abstract class EntityMigration extends Modifier
             _columnName = columnName;
         }
 
-        public int invoke (Connection conn) throws SQLException {
+        public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
             if (!JDBCUtil.tableContainsColumn(conn, _tableName, _columnName)) {
                 // we'll accept this inconsistency
                 log.warning(_tableName + "." + _columnName + " already dropped.");
                 return 0;
             }
 
-            Statement stmt = conn.createStatement();
-            try {
             log.info("Dropping '" + _columnName + "' from " + _tableName);
-                return stmt.executeUpdate(
-                    "alter table " + _tableName + " drop column " + _columnName);
-            } finally {
-                stmt.close();
-            }
+            return liaison.dropColumn(conn, _tableName, _columnName) ? 1 : 0;
         }
 
         protected String _columnName;
@@ -78,7 +73,7 @@ public abstract class EntityMigration extends Modifier
             _newColumnName = newColumnName;
         }
 
-        public int invoke (Connection conn) throws SQLException {
+        public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
             if (!JDBCUtil.tableContainsColumn(conn, _tableName, _oldColumnName)) {
                 if (JDBCUtil.tableContainsColumn(conn, _tableName, _newColumnName)) {
                     // we'll accept this inconsistency
@@ -97,60 +92,46 @@ public abstract class EntityMigration extends Modifier
                     _tableName + " already contains '" + _newColumnName + "'");
             }
 
-            Statement stmt = conn.createStatement();
-            try {
-                log.info("Changing '" + _oldColumnName + "' to '" + _newColumnDef + "' in " +
+            log.info("Renaming '" + _oldColumnName + "' to '" + _newColumnName + "' in: " +
                 _tableName);
-                return stmt.executeUpdate("alter table " + _tableName + " change column " +
-                                          _oldColumnName + " " + _newColumnDef);
-            } finally {
-                stmt.close();
-            }
+            return liaison.renameColumn(conn, _tableName, _oldColumnName, _newColumnName) ? 1 : 0;
         }
 
         public boolean runBeforeDefault () {
             return false;
         }
 
-        protected void init (String tableName, HashMap<String,FieldMarshaller> marshallers) {
-            super.init(tableName, marshallers);
-            _newColumnDef = marshallers.get(_newColumnName).getColumnDefinition();
-        }
-
-        protected String _oldColumnName,  _newColumnName, _newColumnDef;
+        protected String _oldColumnName,  _newColumnName;
     }
 
     /**
-     * A convenient migration for changing the type of an existing column.
+     * A convenient migration for changing the type of an existing field. NOTE: This object is
+     * instantiated with the name of a persistent field, not the name of a database column. These
+     * can be very different things for classes that use @Column annotations.
      */
     public static class Retype extends EntityMigration
     {
-        public Retype (int targetVersion, String columnName) {
+        public Retype (int targetVersion, String fieldName) {
             super(targetVersion);
-            _columnName = columnName;
+            _fieldName = fieldName;
         }
 
-        public int invoke (Connection conn) throws SQLException {
-            Statement stmt = conn.createStatement();
-            try {
-                log.info("Updating type of '" + _columnName + "' in " + _tableName);
-                return stmt.executeUpdate("alter table " + _tableName + " change column " +
-                                          _columnName + " " + _newColumnDef);
-            } finally {
-                stmt.close();
-            }
+        public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
+            log.info("Updating type of '" + _fieldName + "' in " + _tableName);
+            return liaison.changeColumn(conn, _tableName, _fieldName, _newColumnDef) ? 1 : 0;
         }
 
         public boolean runBeforeDefault () {
             return false;
         }
 
-        protected void init (String tableName, HashMap<String,FieldMarshaller> marshallers) {
+        protected void init (String tableName, Map<String,FieldMarshaller> marshallers) {
             super.init(tableName, marshallers);
-            _newColumnDef = marshallers.get(_columnName).getColumnDefinition();
+            _columnName = marshallers.get(_fieldName).getColumnName();
+            _newColumnDef = marshallers.get(_fieldName).getColumnDefinition();
         }
 
-        protected String _columnName, _newColumnDef;
+        protected String _fieldName, _columnName, _newColumnDef;
     }
 
     /**
@@ -184,7 +165,7 @@ public abstract class EntityMigration extends Modifier
      * migration has been determined to be runnable so one cannot rely on this method having been
      * called in {@link #shouldRunMigration}.
      */
-    protected void init (String tableName, HashMap<String,FieldMarshaller> marshallers)
+    protected void init (String tableName, Map<String,FieldMarshaller> marshallers)
     {
         _tableName = tableName;
     }

src/java/com/samskivert/jdbc/depot/FieldMarshaller.java

@@ -33,6 +33,7 @@ import java.sql.SQLException;
 import java.sql.Time;
 import java.sql.Timestamp;
 
+import com.samskivert.io.PersistenceException;
 import com.samskivert.jdbc.depot.annotation.Column;
 import com.samskivert.jdbc.depot.annotation.Computed;
 import com.samskivert.jdbc.depot.annotation.GeneratedValue;
@@ -106,10 +107,20 @@ public abstract class FieldMarshaller<T>
                 "Cannot marshall field of type '" + ftype.getName() + "'.");
         }
 
-        marshaller.init(field);
+        marshaller.create(field);
         return marshaller;
     }
 
+    /**
+     * Initializes this field marshaller with a SQL builder which it uses to construct its column
+     * definition according to the appropriate database dialect.
+     */
+    public void init (SQLBuilder builder)
+        throws PersistenceException
+    {
+        _columnDefinition = builder.buildColumnDefinition(this);
+    }
+
     /**
      * Returns the {@link Field} handled by this marshaller.
      */
@@ -194,98 +205,30 @@ public abstract class FieldMarshaller<T>
         writeToObject(po, getFromSet(rset));
     }
 
-    /**
-     * Returns the type used in the SQL column definition for this field.
-     */
-    public abstract String getColumnType ();
-
-    protected void init (Field field)
+    protected void create (Field field)
     {
         _field = field;
         _columnName = field.getName();
 
-        // read our column metadata from the annotation (if it exists); annoyingly we can't create
-        // a Column instance to read the defaults so we have to duplicate them here
-        int length = 255;
-        boolean nullable = false;
-        boolean unique = false;
-        String defval = "";
         Column column = _field.getAnnotation(Column.class);
         if (column != null) {
-            nullable = column.nullable();
-            unique = column.unique();
-            length = column.length();
-            defval = column.defaultValue();
             if (!StringUtil.isBlank(column.name())) {
                 _columnName = column.name();
             }
         }
 
         _computed = field.getAnnotation(Computed.class);
-        // if this field is @Computed, it has no SQL definition
         if (_computed != null) {
-            _columnDefinition = null;
             return;
         }
 
-        // create our SQL column definition
-        StringBuilder builder = new StringBuilder();
-        if (column != null && !StringUtil.isBlank(column.columnDefinition())) {
-            builder.append(column.columnDefinition());
-
-        } else {
-            builder.append(getColumnName());
-            String type = getColumnType();
-            builder.append(" ").append(type);
-
-            // if this is a VARCHAR field, add the length
-            if (type.equals("VARCHAR") || type.equals("VARBINARY")) {
-                builder.append("(").append(length).append(")");
-            }
-
-            // TODO: handle precision and scale
-
-            // handle nullability and uniqueness
-            if (!nullable) {
-                builder.append(" NOT NULL");
-            }
-            if (unique) {
-                builder.append(" UNIQUE");
-            }
-
-            // append the default value if one was specified
-            if (defval.length() > 0) {
-                builder.append(" DEFAULT ").append(defval);
-            }
-        }
-
-        // handle primary keyness
         if (field.getAnnotation(Id.class) != null) {
             // figure out how we're going to generate our primary key values
             _generatedValue = field.getAnnotation(GeneratedValue.class);
-            if (_generatedValue != null) {
-                switch (_generatedValue.strategy()) {
-                case AUTO:
-                case IDENTITY:
-                    builder.append(" AUTO_INCREMENT");
-                    break;
-                case SEQUENCE: // TODO
-                    throw new IllegalArgumentException(
-                        "SEQUENCE key generation strategy not yet supported.");
-                case TABLE:
-                    // nothing to do here, it'll be handled later
-                    break;
         }
     }
-        }
-
-        _columnDefinition = builder.toString();
-    }
 
     protected static class BooleanMarshaller extends FieldMarshaller<Boolean> {
-        public String getColumnType () {
-            return "TINYINT";
-        }
         public Boolean getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getBoolean(po);
@@ -305,9 +248,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class ByteMarshaller extends FieldMarshaller<Byte> {
-        public String getColumnType () {
-            return "TINYINT";
-        }
         public Byte getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getByte(po);
@@ -327,9 +267,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class ShortMarshaller extends FieldMarshaller<Short> {
-        public String getColumnType () {
-            return "SMALLINT";
-        }
         public Short getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getShort(po);
@@ -349,9 +286,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class IntMarshaller extends FieldMarshaller<Integer> {
-        public String getColumnType () {
-            return "INTEGER";
-        }
         public Integer getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getInt(po);
@@ -371,9 +305,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class LongMarshaller extends FieldMarshaller<Long> {
-        public String getColumnType () {
-            return "BIGINT";
-        }
         public Long getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getLong(po);
@@ -393,9 +324,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class FloatMarshaller extends FieldMarshaller<Float> {
-        public String getColumnType () {
-            return "FLOAT";
-        }
         public Float getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getFloat(po);
@@ -415,9 +343,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class DoubleMarshaller extends FieldMarshaller<Double> {
-        public String getColumnType () {
-            return "DOUBLE";
-        }
         public Double getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.getDouble(po);
@@ -437,37 +362,6 @@ public abstract class FieldMarshaller<T>
     }
 
     protected static class ObjectMarshaller extends FieldMarshaller<Object> {
-        public String getColumnType () {
-            Class<?> ftype = _field.getType();
-            if (ftype.equals(Byte.class)) {
-                return "TINYINT";
-            } else if (ftype.equals(Short.class)) {
-                return "SMALLINT";
-            } else if (ftype.equals(Integer.class)) {
-                return "INTEGER";
-            } else if (ftype.equals(Long.class)) {
-                return "BIGINT";
-            } else if (ftype.equals(Float.class)) {
-                return "FLOAT";
-            } else if (ftype.equals(Double.class)) {
-                return "DOUBLE";
-            } else if (ftype.equals(String.class)) {
-                return "VARCHAR";
-            } else if (ftype.equals(Date.class)) {
-                return "DATE";
-            } else if (ftype.equals(Time.class)) {
-                return "DATETIME";
-            } else if (ftype.equals(Timestamp.class)) {
-                return "TIMESTAMP";
-            } else if (ftype.equals(Blob.class)) {
-                return "BLOB";
-            } else if (ftype.equals(Clob.class)) {
-                return "CLOB";
-            } else {
-                throw new IllegalArgumentException(
-                    "Don't know how to create SQL for " + ftype + ".");
-            }
-        }
         public Object getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return _field.get(po);
@@ -503,9 +397,6 @@ public abstract class FieldMarshaller<T>
             throws SQLException {
             ps.setBytes(column, value);
         }
-        public String getColumnType () {
-            return "VARBINARY";
-        }
     }
 
     protected static class IntArrayMarshaller extends FieldMarshaller<int[]> {
@@ -525,9 +416,6 @@ public abstract class FieldMarshaller<T>
             throws SQLException {
             ps.setObject(column, value);
         }
-        public String getColumnType () {
-            return "BLOB";
-        }
     }
 
     protected static class ByteEnumMarshaller extends FieldMarshaller<ByteEnum> {
@@ -545,10 +433,6 @@ public abstract class FieldMarshaller<T>
             }
         }
 
-        public String getColumnType () {
-            return "TINYINT";
-        }
-
         public ByteEnum getFromObject (Object po)
             throws IllegalArgumentException, IllegalAccessException {
             return (ByteEnum) _field.get(po);

src/java/com/samskivert/jdbc/depot/FindAllQuery.java

@@ -33,14 +33,18 @@ import net.sf.ehcache.Cache;
 import net.sf.ehcache.Element;
 
 import com.samskivert.io.PersistenceException;
+import com.samskivert.util.ArrayUtil;
+
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.jdbc.JDBCUtil;
-import com.samskivert.jdbc.depot.operator.Logic.*;
+
 import com.samskivert.jdbc.depot.clause.FieldOverride;
 import com.samskivert.jdbc.depot.clause.Join;
 import com.samskivert.jdbc.depot.clause.QueryClause;
+import com.samskivert.jdbc.depot.clause.SelectClause;
 import com.samskivert.jdbc.depot.clause.Where;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
-import com.samskivert.util.ArrayUtil;
+import com.samskivert.jdbc.depot.operator.Logic.*;
 
 /**
  * This class implements the functionality required by {@link DepotRepository#findAll): fetch
@@ -58,18 +62,20 @@ public abstract class FindAllQuery<T extends PersistentRecord>
             throws PersistenceException
         {
             super(ctx, type);
-            _types = SQLQueryBuilder.getDepotTypes(ctx, type, clauses);
+            DepotTypes types = DepotTypes.getDepotTypes(ctx, clauses);
+            types.addClass(ctx, type);
+            _builder = _ctx.getSQLBuilder(types);
             _clauses = clauses;
         }
 
-        public List<T> invoke (Connection conn) throws SQLException {
-            SQLQueryBuilder<T> keyFieldQuery = new SQLQueryBuilder<T>(
-                    _ctx, _types, _marsh.getPrimaryKeyColumns(), _clauses);
-            PreparedStatement stmt = keyFieldQuery.prepare(conn);
-
+        public List<T> invoke (Connection conn, DatabaseLiaison liaison) throws SQLException
+        {
             Map<Key<T>, T> entities = new HashMap<Key<T>, T>();
             List<Key<T>> allKeys = new ArrayList<Key<T>>();
             List<Key<T>> fetchKeys = new ArrayList<Key<T>>();
+
+            _builder.newQuery(new SelectClause<T>(_type, _marsh.getPrimaryKeyFields(), _clauses));
+            PreparedStatement stmt = _builder.prepare(conn);
             try {
                 ResultSet rs = stmt.executeQuery();
                 while (rs.next()) {
@@ -97,26 +103,28 @@ public abstract class FindAllQuery<T extends PersistentRecord>
 
             if (fetchKeys.size() > 0) {
                 int jj = 0;
-                QueryClause[] newClauses = new QueryClause[_clauses.length + 1];
                 // a select subset of query clauses are preserved for the entity query
+                QueryClause[] newClauses = new QueryClause[_clauses.length + 1];
                 for (int ii = 0; ii < _clauses.length; ii ++) {
                     if (_clauses[ii] instanceof Join || _clauses[ii] instanceof FieldOverride) {
                         newClauses[jj ++] = _clauses[ii];
                     }
                 }
-                SQLExpression[] keyArray = fetchKeys.toArray(new SQLExpression[0]);
+
+                SQLExpression[] keyArray = new SQLExpression[fetchKeys.size()];
+                for (int ii = 0; ii < keyArray.length; ii ++) {
+                    keyArray[ii] = fetchKeys.get(ii).condition;
+                }
 
                 // add our special key-matching where clause
                 newClauses[jj ++] = new Where(new Or(keyArray));
                 newClauses = ArrayUtil.splice(newClauses, jj);
 
                 // build the new query
-                SQLQueryBuilder<T> entityQuery = new SQLQueryBuilder<T>(
-                        _ctx, _types, _marsh.getFieldNames(), newClauses);
+                _builder.newQuery(new SelectClause<T>(_type, _marsh.getFieldNames(), newClauses));
+                stmt = _builder.prepare(conn);
 
                 // and execute it
-                stmt = entityQuery.prepare(conn);
-
                 try {
                     ResultSet rs = stmt.executeQuery();
                     for (Key<T> key : fetchKeys) {
@@ -138,7 +146,6 @@ public abstract class FindAllQuery<T extends PersistentRecord>
             return result;
         }
 
-        protected DepotTypes<T> _types;
         protected QueryClause[] _clauses;
     }
 
@@ -151,33 +158,32 @@ public abstract class FindAllQuery<T extends PersistentRecord>
             throws PersistenceException
         {
             super(ctx, type);
-            DepotTypes<List<T>> types = SQLQueryBuilder.getDepotTypes(ctx, type, clauses);
-            _builder = new SQLQueryBuilder<List<T>>(ctx, types, _marsh.getFieldNames(), clauses);
+            SelectClause<T> select = new SelectClause<T>(type, _marsh.getFieldNames(), clauses);
+            _builder = ctx.getSQLBuilder(DepotTypes.getDepotTypes(ctx, select));
+            _builder.newQuery(select);
         }
 
-        public List<T> invoke (Connection conn) throws SQLException {
-            PreparedStatement stmt = _builder.prepare(conn);
-
+        public List<T> invoke (Connection conn, DatabaseLiaison liaison) throws SQLException
+        {
             List<T> result = new ArrayList<T>();
+            PreparedStatement stmt = _builder.prepare(conn);
             try {
                 ResultSet rs = stmt.executeQuery();
                 while (rs.next()) {
                     result.add(_marsh.createObject(rs));
                 }
-
             } finally {
                 JDBCUtil.close(stmt);
             }
             return result;
         }
-
-        protected SQLQueryBuilder<List<T>> _builder;
     }
 
     public FindAllQuery (PersistenceContext ctx, Class<T> type)
         throws PersistenceException
     {
         _ctx = ctx;
+        _type = type;
         _marsh = _ctx.getMarshaller(type);
     }
 
@@ -216,5 +222,7 @@ public abstract class FindAllQuery<T extends PersistentRecord>
     }
 
     protected PersistenceContext _ctx;
+    protected SQLBuilder _builder;
     protected DepotMarshaller<T> _marsh;
+    protected Class<T> _type;
 }

src/java/com/samskivert/jdbc/depot/FindOneQuery.java

@@ -26,8 +26,11 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 
 import com.samskivert.io.PersistenceException;
+
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.jdbc.JDBCUtil;
 import com.samskivert.jdbc.depot.clause.QueryClause;
+import com.samskivert.jdbc.depot.clause.SelectClause;
 
 /**
  * The implementation of {@link DepotRepository#find) functionality.
@@ -39,21 +42,23 @@ public class FindOneQuery<T extends PersistentRecord>
         throws PersistenceException
     {
         _marsh = ctx.getMarshaller(type);
-        DepotTypes<T> types = SQLQueryBuilder.getDepotTypes(ctx, type, clauses);
-        _builder = new SQLQueryBuilder<T>(ctx, types, _marsh.getFieldNames(), clauses);
+        _select = new SelectClause<T>(type, _marsh.getFieldNames(), clauses);
+        _builder = ctx.getSQLBuilder(DepotTypes.getDepotTypes(ctx, _select));
+        _builder.newQuery(_select);
     }
 
     // from Query
     public CacheKey getCacheKey ()
     {
-        if (_builder.where != null && _builder.where instanceof CacheKey) {
-            return (CacheKey) _builder.where;
+        WhereClause where = _select.getWhereClause();
+        if (where != null && where instanceof CacheKey) {
+            return (CacheKey) where;
         }
         return null;
     }
 
     // from Query
-    public T invoke (Connection conn) throws SQLException {
+    public T invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
         PreparedStatement stmt = _builder.prepare(conn);
         try {
             T result = null;
@@ -96,5 +101,6 @@ public class FindOneQuery<T extends PersistentRecord>
     }
 
     protected DepotMarshaller<T> _marsh;
-    protected SQLQueryBuilder<T> _builder;
+    protected SelectClause<T> _select;
+    protected SQLBuilder _builder;
 }

src/java/com/samskivert/jdbc/depot/IdentityKeyGenerator.java

@@ -21,17 +21,22 @@
 package com.samskivert.jdbc.depot;
 
 import java.sql.Connection;
-import java.sql.ResultSet;
 import java.sql.SQLException;
-import java.sql.Statement;
 
-import com.samskivert.jdbc.JDBCUtil;
+import com.samskivert.jdbc.DatabaseLiaison;
+import com.samskivert.jdbc.LiaisonRegistry;
+import com.samskivert.jdbc.depot.annotation.GeneratedValue;
 
 /**
  * Generates primary keys using an identity column.
  */
-public class IdentityKeyGenerator implements KeyGenerator
+public class IdentityKeyGenerator extends KeyGenerator
 {
+    public IdentityKeyGenerator (GeneratedValue gv, String table, String column)
+    {
+        super(gv, table, column);
+    }
+
     // from interface KeyGenerator
     public boolean isPostFactum ()
     {
@@ -39,27 +44,16 @@ public class IdentityKeyGenerator implements KeyGenerator
     }
 
     // from interface KeyGenerator
-    public void init (Connection conn)
+    public void init (Connection conn, DatabaseLiaison liaison)
         throws SQLException
     {
-        // nothing to do here
+        liaison.initializeGenerator(conn, _table, _column, _initialValue, _allocationSize);
     }
 
     // from interface KeyGenerator
-    public int nextGeneratedValue (Connection conn)
+    public int nextGeneratedValue (Connection conn, DatabaseLiaison liaison)
         throws SQLException
     {
-        // load up the last inserted ID mysql style
-        Statement stmt = conn.createStatement();
-        try {
-            ResultSet rs = stmt.executeQuery("select LAST_INSERT_ID()");
-            if (rs.next()) {
-                return rs.getInt(1);
-            }
-            throw new SQLException("Failed to generate next ID");
-
-        } finally {
-            JDBCUtil.close(stmt);
-        }
+        return liaison.lastInsertedId(conn, _table, _column);
     }
 }

src/java/com/samskivert/jdbc/depot/Key.java

@@ -22,8 +22,6 @@ package com.samskivert.jdbc.depot;
 
 import java.io.Serializable;
 import java.lang.reflect.Field;
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -31,20 +29,77 @@ import java.util.HashMap;
 import java.util.Map;
 
 import com.samskivert.jdbc.depot.annotation.Id;
-import com.samskivert.jdbc.depot.clause.Where;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 import com.samskivert.util.StringUtil;
 
 /**
- * A special form of {@link Where} clause that uniquely specifies a single database row and
+ * A special form of {@link WhereClause} that uniquely specifies a single database row and
  * thus also a single persistent object. Because it implements both {@link CacheKey} and
  * {@link CacheInvalidator} it also uniquely indexes into the cache and knows how to invalidate
  * itself upon modification. This class is created by many {@link DepotMarshaller} methods as
  * a convenience, and may also be instantiated explicitly.
  */
-public class Key<T extends PersistentRecord> extends Where
+public class Key<T extends PersistentRecord> extends WhereClause
     implements SQLExpression, CacheKey, CacheInvalidator, Serializable
 {
+    /** An expression that contains our key columns and values. */
+    public static class WhereCondition<U extends PersistentRecord> implements SQLExpression
+    {
+        public WhereCondition (Class<U> pClass, Comparable[] values)
+        {
+            _pClass = pClass;
+            _values = values;
+        }
+
+        // from SQLExpression
+        public void accept (ExpressionVisitor builder)
+            throws Exception
+        {
+            builder.visit(this);
+        }
+
+        // from SQLExpression
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+        {
+        }
+
+        public Class<U> getPersistentClass ()
+        {
+            return _pClass;
+        }
+
+        public Comparable[] getValues ()
+        {
+            return _values;
+        }
+
+        @Override
+        public boolean equals (Object obj)
+        {
+            if (this == obj) {
+                return true;
+            }
+            if (obj == null || getClass() != obj.getClass()) {
+                return false;
+            }
+            WhereCondition other = (WhereCondition) obj;
+            return _pClass == other._pClass && Arrays.equals(_values, other._values);
+        }
+
+        @Override
+        public int hashCode ()
+        {
+            return _pClass.hashCode() ^ Arrays.hashCode(_values);
+        }
+
+        protected Class<U> _pClass;
+        protected Comparable[] _values;
+    }
+
+    /** The expression that identifies our row. */
+    public final WhereCondition<T> condition;
+
     /**
      * Constructs a new single-column {@code Key} with the given value.
      */
@@ -76,10 +131,6 @@ public class Key<T extends PersistentRecord> extends Where
      */
     public Key (Class<T> pClass, String[] fields, Comparable[] values)
     {
-        // TODO: make Where an interface so we don't have to do this ugly super call
-        super(null);
-        _pClass = pClass;
-
         if (fields.length != values.length) {
             throw new IllegalArgumentException("Field and Value arrays must be of equal length.");
         }
@@ -94,69 +145,41 @@ public class Key<T extends PersistentRecord> extends Where
         String[] keyFields = getKeyFields(pClass);
 
         // now extract the values in field order and ensure none are extra or missing
-        _values = new Comparable[fields.length];
+        Comparable[] newValues = new Comparable[fields.length];
         for (int ii = 0; ii < keyFields.length; ii++) {
-            _values[ii] = map.remove(keyFields[ii]);
+            newValues[ii] = map.remove(keyFields[ii]);
             // make sure we were provided with a value for this primary key field
-            if (_values[ii] == null) {
+            if (newValues[ii] == null) {
                 throw new IllegalArgumentException("Missing value for key field: " + keyFields[ii]);
             }
         }
+
         // finally make sure we were not given any fields that are not in fact primary key fields
         if (map.size() > 0) {
             throw new IllegalArgumentException(
                 "Non-key columns given: " +  StringUtil.join(map.keySet().toArray(), ", "));
         }
+
+        condition = new WhereCondition<T>(pClass, newValues);
     }
 
-    // from QueryClause
+    // from SQLExpression
     public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        classSet.add(_pClass);
-    }
-
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
-    {
-        builder.append(" where ");
-        appendExpression(query, builder);
-    }
-
-    // from QueryClause
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
-    {
-        for (int ii = 0; ii < _values.length; ii ++) {
-            if (_values[ii] != null) {
-                pstmt.setObject(argIdx ++, _values[ii]);
-            }
-        }
-        return argIdx;
+        classSet.add(condition.getPersistentClass());
     }
 
     // from SQLExpression
-    public void appendExpression (QueryBuilderContext<?> query, StringBuilder builder)
+    public void accept (ExpressionVisitor builder)
+        throws Exception
     {
-        String[] keyFields = getKeyFields(_pClass);
-        for (int ii = 0; ii < keyFields.length; ii ++) {
-            if (ii > 0) {
-                builder.append(" and ");
-            }
-            builder.append(keyFields[ii]).append(_values[ii] == null ? " is null " : " = ? ");
-        }
-    }
-
-    // from SQLExpression
-    public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
-    {
-        return bindClauseArguments(pstmt, argIdx);
+        builder.visit(this);
     }
 
     // from CacheKey
     public String getCacheId ()
     {
-        return _pClass.getName();
+        return condition.getPersistentClass().getName();
     }
 
     // from CacheKey
@@ -171,12 +194,6 @@ public class Key<T extends PersistentRecord> extends Where
         ctx.cacheInvalidate(this);
     }
 
-    @Override
-    public int hashCode ()
-    {
-        return _pClass.hashCode() ^ Arrays.hashCode(_values);
-    }
-
     @Override
     public boolean equals (Object obj)
     {
@@ -186,17 +203,24 @@ public class Key<T extends PersistentRecord> extends Where
         if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
-        Key other = (Key) obj;
-        return _pClass == other._pClass && Arrays.equals(_values, other._values);
+        return condition.equals(((Key) obj).condition);
+    }
+
+    @Override
+    public int hashCode ()
+    {
+        return condition.hashCode();
     }
 
     @Override
     public String toString ()
     {
-        StringBuilder builder = new StringBuilder("[Key pClass=" + _pClass.getName());
-        String[] keyFields = getKeyFields(_pClass);
+        StringBuilder builder =
+            new StringBuilder("[Key pClass=").append(condition.getPersistentClass().getName());
+        String[] keyFields = getKeyFields(condition.getPersistentClass());
         for (int ii = 0; ii < keyFields.length; ii ++) {
-            builder.append(", ").append(keyFields[ii]).append("=").append(_values[ii]);
+            builder.append(", ").append(keyFields[ii]).append("=").
+                append(condition.getValues()[ii]);
         }
         builder.append("]");
         return builder.toString();
@@ -222,9 +246,6 @@ public class Key<T extends PersistentRecord> extends Where
         return fields;
     }
 
-    protected Class<T> _pClass;
-    protected Comparable[] _values;
-
     /** A (never expiring) cache of primary key field names for all persistent classes (of which
      * there are merely dozens, so we don't need to worry about expiring). */
     protected static HashMap<Class<?>,String[]> _keyFields = new HashMap<Class<?>,String[]>();

src/java/com/samskivert/jdbc/depot/KeyGenerator.java

@@ -23,18 +23,58 @@ package com.samskivert.jdbc.depot;
 import java.sql.Connection;
 import java.sql.SQLException;
 
+import com.samskivert.jdbc.DatabaseLiaison;
+import com.samskivert.jdbc.depot.annotation.GeneratedValue;
+
 /**
  * Defines the interface to our primary key generators.
  */
-public interface KeyGenerator
+public abstract class KeyGenerator
 {
-    /** If true, this key generator will be run after the insert statement, if false, it will be
-     * run before. */
-    public boolean isPostFactum ();
+    public KeyGenerator (GeneratedValue gv, String table, String column)
+    {
+        _allocationSize = gv.allocationSize();
+        _initialValue = gv.initialValue();
+        _table = table;
+        _column = column;
+    }
 
-    /** Prepares the generator for operation. */
-    public void init (Connection conn) throws SQLException;
+    /**
+     * If true, this key generator will be run after the insert statement, if false, it will be run
+     * before.
+     */
+    public abstract boolean isPostFactum ();
 
-    /** Fetch/generate the next primary key value. */
-    public int nextGeneratedValue (Connection conn) throws SQLException;
+    /**
+     * Prepares the generator for operation.
+     */
+    public abstract void init (Connection conn, DatabaseLiaison liaison)
+        throws SQLException;
+
+    /**
+     * Fetch/generate the next primary key value.
+     */
+    public abstract int nextGeneratedValue (Connection conn, DatabaseLiaison liaison)
+        throws SQLException;
+
+    /**
+     * Returns the name of the table for which we're generating a key value.
+     */
+    public String getTable ()
+    {
+        return _table;
+    }
+
+    /**
+     * Returns the name of the column for which we're generating a key value.
+     */
+    public String getColumn ()
+    {
+        return _column;
+    }
+
+    protected int _initialValue;
+    protected int _allocationSize;
+    protected String _table;
+    protected String _column;
 }

src/java/com/samskivert/jdbc/depot/Modifier.java

@@ -24,6 +24,8 @@ import java.sql.Connection;
 import java.sql.SQLException;
 import java.sql.Statement;
 
+import com.samskivert.jdbc.DatabaseLiaison;
+
 /**
  * Encapsulates a modification of persistent objects.
  */
@@ -33,23 +35,22 @@ public abstract class Modifier
      * A simple modifier that executes a single SQL statement. No cache flushing is done as a
      * result of this operation.
      */
-    public static class Simple extends Modifier
+    public abstract static class Simple extends Modifier
     {
-        public Simple (String query) {
+        public Simple () {
             super(null);
-            _query = query;
         }
 
-        public int invoke (Connection conn) throws SQLException {
+        public int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException {
             Statement stmt = conn.createStatement();
             try {
-                return stmt.executeUpdate(_query);
+                return stmt.executeUpdate(createQuery(liaison));
             } finally {
                 stmt.close();
             }
         }
 
-        protected String _query;
+        protected abstract String createQuery (DatabaseLiaison liaison);
     }
 
     /**
@@ -98,10 +99,10 @@ public abstract class Modifier
     }
 
     /**
-     * Overriden to perform the actual database modifications represented by this object;
-     * should return the number of modified rows.
+     * Overriden to perform the actual database modifications represented by this object; should
+     * return the number of modified rows.
      */
-    public abstract int invoke (Connection conn) throws SQLException;
+    public abstract int invoke (Connection conn, DatabaseLiaison liaison) throws SQLException;
 
     /**
      * Constructs a {@link Modifier} without a cache invalidator.

src/java/com/samskivert/jdbc/depot/MultiKey.java

@@ -20,21 +20,19 @@
 
 package com.samskivert.jdbc.depot;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
 import com.samskivert.jdbc.depot.clause.Where;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 
 /**
  * A special form of {@link Where} clause that specifies an explicit range of database rows. It
  * does not implement {@link CacheKey} but it does implement {@link CacheInvalidator} which means
  * it can be sent into e.g. {@link DepotRepository#deleteAll) and have it clean up after itself.
  */
-public class MultiKey<T extends PersistentRecord> extends Where
+public class MultiKey<T extends PersistentRecord> extends WhereClause
     implements CacheInvalidator
 {
     /**
@@ -69,8 +67,6 @@ public class MultiKey<T extends PersistentRecord> extends Where
     public MultiKey (Class<T> pClass, String[] sFields, Comparable[] sValues,
                      String mField, Comparable[] mValues)
     {
-        // TODO
-        super(null);
         if (sFields.length != sValues.length) {
             throw new IllegalArgumentException(
                 "Key field and values arrays must be of equal length.");
@@ -84,52 +80,16 @@ public class MultiKey<T extends PersistentRecord> extends Where
         }
     }
 
-    @Override // from QueryClause
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    // from SQLExpression
     public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        classSet.add(_pClass);
-    }
-
-    @Override // from Where
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
-    {
-        builder.append(" where ");
-        boolean first = true;
-        for (Map.Entry entry : _map.entrySet()) {
-            if (first) {
-                first = false;
-            } else {
-                builder.append(" and ");
-            }
-            builder.append(entry.getKey());
-            builder.append(entry.getValue() == null ? " is null " : " = ? ");
-        }
-        if (!first) {
-            builder.append(" and ");
-        }
-        builder.append(_mField).append(" in (");
-        for (int ii = 0; ii < _mValues.length; ii ++) {
-            if (ii > 0) {
-                builder.append(", ");
-            }
-            builder.append("?");
-        }
-        builder.append(")");
-    }
-
-    @Override // from Where
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
-    {
-        for (Map.Entry entry : _map.entrySet()) {
-            if (entry.getValue() != null) {
-                pstmt.setObject(argIdx ++, entry.getValue());
-            }
-        }
-        for (int ii = 0; ii < _mValues.length; ii++) {
-            pstmt.setObject(argIdx ++, _mValues[ii]);
-        }
-        return argIdx;
+        // nothing to add
     }
 
     // from CacheInvalidator
@@ -142,8 +102,28 @@ public class MultiKey<T extends PersistentRecord> extends Where
         }
     }
 
-    protected Class<T> _pClass;
-    protected HashMap<String, Comparable> _map;
+    public Class<T> getPersistentClass ()
+    {
+        return _pClass;
+    }
+
+    public Map<String, Comparable> getSingleFieldsMap ()
+    {
+        return _map;
+    }
+
+    public String getMultiField ()
+    {
+        return _mField;
+    }
+
+    public Comparable[] getMultiValues ()
+    {
+        return _mValues;
+    }
+
     protected String _mField;
     protected Comparable[] _mValues;
+    protected Class<T> _pClass;
+    protected HashMap<String, Comparable> _map;
 }

src/java/com/samskivert/jdbc/depot/MySQLBuilder.java

@@ -0,0 +1,191 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot;
+
+import java.sql.Blob;
+import java.sql.Clob;
+import java.sql.Date;
+import java.sql.PreparedStatement;
+import java.sql.Time;
+import java.sql.Timestamp;
+
+import com.samskivert.jdbc.depot.FieldMarshaller.BooleanMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ByteArrayMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ByteEnumMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ByteMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.DoubleMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.FloatMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.IntArrayMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.IntMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.LongMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ObjectMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ShortMarshaller;
+import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.operator.Conditionals.Match;
+
+public class MySQLBuilder
+    extends SQLBuilder
+{
+    public class MSBuildVisitor extends BuildVisitor
+    {
+        protected MSBuildVisitor (DepotTypes types)
+        {
+            super(types);
+        }
+
+        @Override
+        public void visit (Match match)
+            throws Exception
+        {
+            _builder.append("match(");
+            ColumnExp[] columns = match.getColumns();
+            for (int ii = 0; ii < columns.length; ii ++) {
+                if (ii > 0) {
+                    _builder.append(", ");
+                }
+                columns[ii].accept(this);
+            }
+            _builder.append(") against (?");
+            switch (match.getMode()) {
+            case BOOLEAN:
+                _builder.append(" in boolean mode");
+                break;
+            case NATURAL_LANGUAGE:
+                _builder.append(" in natural language mode");
+                break;
+            }
+            if (match.isQueryExpansion()) {
+                _builder.append(" with query expansion");
+            }
+            _builder.append(")");
+        }
+
+        protected void appendTableName (Class<? extends PersistentRecord> type)
+        {
+            _builder.append(_types.getTableName(type));
+        }
+
+        protected void appendTableAbbreviation (Class<? extends PersistentRecord> type)
+        {
+            _builder.append(_types.getTableAbbreviation(type));
+        }
+
+        protected void appendColumn (Class<? extends PersistentRecord> type, String field)
+        {
+            _builder.append(_types.getColumnName(type, field));
+        }
+
+        protected void appendField (String field)
+        {
+            _builder.append(field);
+        }
+    }
+
+    public class MSBindVisitor extends BindVisitor
+    {
+        protected MSBindVisitor (DepotTypes types, PreparedStatement stmt)
+        {
+            super(types, stmt);
+        }
+
+        @Override
+        public void visit (Match match)
+            throws Exception
+        {
+            _stmt.setString(_argIdx ++, match.getQuery());
+        }
+    }
+
+    public MySQLBuilder (DepotTypes types)
+    {
+        super(types);
+    }
+
+    @Override
+    protected BuildVisitor getBuildVisitor ()
+    {
+        return new MSBuildVisitor(_types);
+    }
+
+    @Override
+    protected BindVisitor getBindVisitor (PreparedStatement stmt)
+    {
+        return new MSBindVisitor(_types, stmt);
+    }
+
+    @Override
+    protected <T> String getColumnType (FieldMarshaller fm)
+    {
+        if (fm instanceof ByteMarshaller) {
+            return "TINYINT";
+        } else if (fm instanceof ShortMarshaller) {
+            return "SMALLINT";
+        } else if (fm instanceof IntMarshaller) {
+            return "INTEGER";
+        } else if (fm instanceof LongMarshaller) {
+            return "BIGINT";
+        } else if (fm instanceof FloatMarshaller) {
+            return "FLOAT";
+        } else if (fm instanceof DoubleMarshaller) {
+            return "DOUBLE";
+        } else if (fm instanceof ObjectMarshaller) {
+            Class<?> ftype = fm.getField().getType();
+            if (ftype.equals(Byte.class)) {
+                return "SMALLINT";
+            } else if (ftype.equals(Short.class)) {
+                return "SMALLINT";
+            } else if (ftype.equals(Integer.class)) {
+                return "INTEGER";
+            } else if (ftype.equals(Long.class)) {
+                return "BIGINT";
+            } else if (ftype.equals(Float.class)) {
+                return "FLOAT";
+            } else if (ftype.equals(Double.class)) {
+                return "DOUBLE";
+            } else if (ftype.equals(String.class)) {
+                return "VARCHAR";
+            } else if (ftype.equals(Date.class)) {
+                return "DATE";
+            } else if (ftype.equals(Time.class)) {
+                return "DATETIME";
+            } else if (ftype.equals(Timestamp.class)) {
+                return "DATETIME";
+            } else if (ftype.equals(Blob.class)) {
+                return "BYTEA";
+            } else if (ftype.equals(Clob.class)) {
+                return "TEXT";
+            } else {
+                throw new IllegalArgumentException(
+                    "Don't know how to create SQL for " + ftype + ".");
+            }
+        } else if (fm instanceof ByteArrayMarshaller) {
+            return "VARBINARY";
+        } else if (fm instanceof IntArrayMarshaller) {
+            return "BLOB";
+        } else if (fm instanceof ByteEnumMarshaller) {
+            return "TINYINT";
+        } else if (fm instanceof BooleanMarshaller) {
+            return "TINYINT";
+        } else {
+            throw new IllegalArgumentException("Unknown field marshaller type: " + fm.getClass());
+        }
+    }
+}

src/java/com/samskivert/jdbc/depot/PersistenceContext.java

@@ -40,8 +40,11 @@ import com.samskivert.io.PersistenceException;
 import com.samskivert.util.StringUtil;
 
 import com.samskivert.jdbc.ConnectionProvider;
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.jdbc.DuplicateKeyException;
-
+import com.samskivert.jdbc.LiaisonRegistry;
+import com.samskivert.jdbc.MySQLLiaison;
+import com.samskivert.jdbc.PostgreSQLLiaison;
 
 /**
  * Defines a scope in which global annotations are shared.
@@ -124,6 +127,23 @@ public class PersistenceContext
         _ident = ident;
         _conprov = conprov;
         _cachemgr = CacheManager.getInstance();
+        _liaison = LiaisonRegistry.getLiaison(conprov.getURL(ident));
+    }
+
+    /**
+     * Create and return a new {@link SQLBuilder} for the appropriate dialect.
+     *
+     * TODO: At some point perhaps use a more elegant way of discerning our dialect.
+     */
+    public SQLBuilder getSQLBuilder (DepotTypes types)
+    {
+        if (_liaison instanceof PostgreSQLLiaison) {
+            return new PostgreSQLBuilder(types);
+        }
+        if (_liaison instanceof MySQLLiaison) {
+            return new MySQLBuilder(types);
+        }
+        throw new IllegalArgumentException("Unknown liaison type: " + _liaison.getClass());
     }
 
     /**
@@ -399,25 +419,21 @@ public class PersistenceContext
         Connection conn = _conprov.getConnection(_ident, isReadOnlyQuery);
         try {
             if (isReadOnlyQuery) {
-                // if this becomes more complex than this single statement,
-                // then this should turn into a method call that contains
-                // the complexity
-                return query.invoke(conn);
+                // if this becomes more complex than this single statement, then this should turn
+                // into a method call that contains the complexity
+                return query.invoke(conn, _liaison);
 
             } else {
-                // if this becomes more complex than this single statement,
-                // then this should turn into a method call that contains
-                // the complexity
-                return modifier.invoke(conn);
+                // if this becomes more complex than this single statement, then this should turn
+                // into a method call that contains the complexity
+                return modifier.invoke(conn, _liaison);
             }
 
         } catch (SQLException sqe) {
             if (!isReadOnlyQuery) {
-                // convert this exception to a DuplicateKeyException if
-                // appropriate
-                String msg = sqe.getMessage();
-                if (msg != null && msg.indexOf("Duplicate entry") != -1) {
-                    throw new DuplicateKeyException(msg);
+                // convert this exception to a DuplicateKeyException if appropriate
+                if (_liaison.isDuplicateRowException(sqe)) {
+                    throw new DuplicateKeyException(sqe.getMessage());
                 }
             }
 
@@ -425,7 +441,7 @@ public class PersistenceContext
             _conprov.connectionFailed(_ident, isReadOnlyQuery, conn, sqe);
             conn = null;
 
-            if (retryOnTransientFailure && isTransientException(sqe)) {
+            if (retryOnTransientFailure && _liaison.isTransientException(sqe)) {
                 // the MySQL JDBC driver has the annoying habit of including
                 // the embedded exception stack trace in the message of their
                 // outer exception; if I want a fucking stack trace, I'll call
@@ -448,21 +464,10 @@ public class PersistenceContext
         return invoke(query, modifier, false);
     }
 
-    /**
-     * Check whether the specified exception is a transient failure that can be retried.
-     */
-    protected boolean isTransientException (SQLException sqe)
-    {
-        // TODO: this is MySQL specific. This was snarfed from MySQLLiaison.
-        String msg = sqe.getMessage();
-        return (msg != null && (msg.indexOf("Lost connection") != -1 ||
-                                msg.indexOf("link failure") != -1 ||
-                                msg.indexOf("Broken pipe") != -1));
-    }
-
     protected String _ident;
     protected ConnectionProvider _conprov;
     protected CacheManager _cachemgr;
+    protected DatabaseLiaison _liaison;
 
     protected Map<String, Set<CacheListener<?>>> _listenerSets =
         new HashMap<String, Set<CacheListener<?>>>();

src/java/com/samskivert/jdbc/depot/PostgreSQLBuilder.java

@@ -0,0 +1,155 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot;
+
+import java.sql.Blob;
+import java.sql.Clob;
+import java.sql.Date;
+import java.sql.PreparedStatement;
+import java.sql.Time;
+import java.sql.Timestamp;
+
+import com.samskivert.jdbc.depot.FieldMarshaller.BooleanMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ByteArrayMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ByteEnumMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ByteMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.DoubleMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.FloatMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.IntArrayMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.IntMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.LongMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ObjectMarshaller;
+import com.samskivert.jdbc.depot.FieldMarshaller.ShortMarshaller;
+
+public class PostgreSQLBuilder
+    extends SQLBuilder
+{
+    public class PGBuildVisitor extends BuildVisitor
+    {
+        protected PGBuildVisitor (DepotTypes types)
+        {
+            super(types);
+        }
+
+        protected void appendTableName (Class<? extends PersistentRecord> type)
+        {
+            _builder.append("\"").append(_types.getTableName(type)).append("\"");
+        }
+
+        protected void appendTableAbbreviation (Class<? extends PersistentRecord> type)
+        {
+            _builder.append("\"").append(_types.getTableAbbreviation(type)).append("\"");
+        }
+
+        protected void appendColumn (Class<? extends PersistentRecord> type, String field)
+        {
+            _builder.append("\"").append(_types.getColumnName(type, field)).append("\"");
+        }
+
+        protected void appendField (String field)
+        {
+            _builder.append("\"").append(field).append("\"");
+        }
+    }
+
+    public class PGBindVisitor extends BindVisitor
+    {
+        protected PGBindVisitor (DepotTypes types, PreparedStatement stmt)
+        {
+            super(types, stmt);
+        }
+    }
+
+    public PostgreSQLBuilder (DepotTypes types)
+    {
+        super(types);
+    }
+
+    @Override
+    protected BuildVisitor getBuildVisitor ()
+    {
+        return new PGBuildVisitor(_types);
+    }
+
+    @Override
+    protected BindVisitor getBindVisitor (PreparedStatement stmt)
+    {
+        return new PGBindVisitor(_types, stmt);
+    }
+
+    @Override
+    protected <T> String getColumnType (FieldMarshaller fm)
+    {
+        if (fm instanceof ByteMarshaller) {
+            return "SMALLINT";
+        } else if (fm instanceof ShortMarshaller) {
+            return "SMALLINT";
+        } else if (fm instanceof IntMarshaller) {
+            return "INTEGER";
+        } else if (fm instanceof LongMarshaller) {
+            return "BIGINT";
+        } else if (fm instanceof FloatMarshaller) {
+            return "FLOAT";
+        } else if (fm instanceof DoubleMarshaller) {
+            return "DOUBLE";
+        } else if (fm instanceof ObjectMarshaller) {
+            Class<?> ftype = fm.getField().getType();
+            if (ftype.equals(Byte.class)) {
+                return "SMALLINT";
+            } else if (ftype.equals(Short.class)) {
+                return "SMALLINT";
+            } else if (ftype.equals(Integer.class)) {
+                return "INTEGER";
+            } else if (ftype.equals(Long.class)) {
+                return "BIGINT";
+            } else if (ftype.equals(Float.class)) {
+                return "FLOAT";
+            } else if (ftype.equals(Double.class)) {
+                return "DOUBLE";
+            } else if (ftype.equals(String.class)) {
+                return "VARCHAR";
+            } else if (ftype.equals(Date.class)) {
+                return "DATE";
+            } else if (ftype.equals(Time.class)) {
+                return "TIME";
+            } else if (ftype.equals(Timestamp.class)) {
+                return "TIMESTAMP";
+            } else if (ftype.equals(Blob.class)) {
+                return "BYTEA";
+            } else if (ftype.equals(Clob.class)) {
+                return "TEXT";
+            } else {
+                throw new IllegalArgumentException(
+                    "Don't know how to create SQL for " + ftype + ".");
+            }
+        } else if (fm instanceof ByteArrayMarshaller) {
+            return "BYTEA";
+        } else if (fm instanceof IntArrayMarshaller) {
+            return "BYTEA";
+        } else if (fm instanceof ByteEnumMarshaller) {
+            return "SMALLINT";
+        } else if (fm instanceof BooleanMarshaller) {
+            return "BOOLEAN";
+        } else {
+            throw new IllegalArgumentException("Unknown field marshaller type: " + fm.getClass());
+        }
+    }
+}

src/java/com/samskivert/jdbc/depot/Query.java

@@ -23,11 +23,30 @@ package com.samskivert.jdbc.depot;
 import java.sql.Connection;
 import java.sql.SQLException;
 
+import com.samskivert.jdbc.DatabaseLiaison;
+
 /**
  * The base of all read-only queries.
  */
 public interface Query<T>
 {
+    /** A simple base class for non-complex queries. */
+    public abstract class TrivialQuery<T> implements Query<T>
+    {
+        public abstract T invoke (Connection conn, DatabaseLiaison liaison) throws SQLException;
+
+        public CacheKey getCacheKey () {
+            return null;
+        }
+
+        public T transformCacheHit (CacheKey key, T value) {
+            return value;
+        }
+
+        public void updateCache (PersistenceContext ctx, T result) {
+        }
+    }
+    
     /**
      * Any query may elect to utilize the built-in cache by returning a non-null {@link CacheKey}
      * in this method. This is done automatically by the {@link DepotRepository} when looking up
@@ -43,7 +62,7 @@ public interface Query<T>
     /**
      * Performs the actual JDBC operations associated with this query. 
      */
-    public T invoke (Connection conn)
+    public T invoke (Connection conn, DatabaseLiaison liaison)
         throws SQLException;
 
     /**

src/java/com/samskivert/jdbc/depot/QueryBuilderContext.java

@@ -1,43 +0,0 @@
-//
-// $Id$
-//
-// samskivert library - useful routines for java programs
-// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
-// 
-// This library is free software; you can redistribute it and/or modify it
-// under the terms of the GNU Lesser General Public License as published
-// by the Free Software Foundation; either version 2.1 of the License, or
-// (at your option) any later version.
-//
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-// Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public
-// License along with this library; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-
-package com.samskivert.jdbc.depot;
-
-/**
- * This type is used during the construction of SQL queries to map persistent classes
- * to table names and table abbreviations. Its primary implementation is {@link DepotTypes}.
- */
-public interface QueryBuilderContext<T>
-{
-    /**
-     * Maps a class referenced by this query to its associated table.
-     *
-     * This method is called by individual clauses.
-     */
-    public String getTableName (Class<? extends PersistentRecord> cl);
-
-    /**
-     * Maps a class referenced by this query to the abbreviation used for its associated table. The
-     * abbreviation is meaningful only within the scope of this particular query.
-     *
-     * This method is called by individual clauses.
-     */
-    public String getTableAbbreviation (Class<? extends PersistentRecord> cl);
-}

src/java/com/samskivert/jdbc/depot/SQLBuilder.java

@@ -0,0 +1,195 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot;
+
+import java.lang.reflect.Field;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+import com.samskivert.jdbc.depot.annotation.Column;
+import com.samskivert.jdbc.depot.annotation.GeneratedValue;
+import com.samskivert.jdbc.depot.clause.QueryClause;
+
+/**
+ * At the heart of Depot's SQL generation, this object constructs two {@link ExpressionVisitor}
+ * objects and executes them, one after another; the first one constructs SQL as it recurses, the
+ * other binds arguments in the {@link PreparedStatement}. This class must be subclassed by the
+ * database dialects we wish to support.
+ */
+public abstract class SQLBuilder
+{
+    public SQLBuilder (DepotTypes types)
+    {
+        _types = types;
+    }
+
+    /**
+     * Construct an entirely new SQL query relative to our configured {@link DepotTypes} data.
+     * This method may be called multiple times, each time beginning a new query, and should be
+     * followed up by a call to {@link #prepare(Connection)} which creates, configures and
+     * returns the actual {@link PreparedStatement} to execute.
+     */
+    public void newQuery (QueryClause clause)
+    {
+        _clause = clause;
+        _buildVisitor = getBuildVisitor();
+
+        try {
+            _clause.accept(_buildVisitor);
+        } catch (Exception e) {
+            throw new RuntimeException("Failed to build SQL", e);
+        }
+    }
+
+    /**
+     * After {@link #newQuery(QueryClause)} has been executed, this method is run to recurse
+     * through the {@link QueryClause} structure, setting the {@link PreparedStatement} arguments
+     * that were defined in the generated SQL.
+     *
+     * This method throws {@link SQLException} and is thus meant to be called from within
+     * {@link Query#invoke(Connection)} and {@link Modifier#invoke(Connection)}.
+     */
+    public PreparedStatement prepare (Connection conn)
+        throws SQLException
+    {
+        if (_buildVisitor == null) {
+            throw new IllegalArgumentException("Cannot prepare query until it's been built.");
+        }
+        PreparedStatement stmt = conn.prepareStatement(_buildVisitor.getQuery());
+        _bindVisitor = getBindVisitor(stmt);
+
+        try {
+            _clause.accept(_bindVisitor);
+        } catch (SQLException se) {
+            throw se;
+        } catch (Exception e) {
+            throw new RuntimeException("Failed to find SQL parameters", e);
+        }
+        return stmt;
+    }
+
+    /**
+     * Generates the SQL needed to construct a database column for field represented by the given
+     * {@link FieldMarshaller}.
+     *
+     * TODO: This method should be split into several parts that are more easily overridden on a
+     * case-by-case basis in the dialectal subclasses.
+     */
+    public <T> String buildColumnDefinition (FieldMarshaller<T> fm)
+    {
+        // if this field is @Computed, it has no SQL definition
+        if (fm.getComputed() != null) {
+            return null;
+        }
+
+        Field field = fm.getField();
+
+        // read our column metadata from the annotation (if it exists); annoyingly we can't create
+        // a Column instance to read the defaults so we have to duplicate them here
+        int length = 255;
+        boolean nullable = false;
+        boolean unique = false;
+        String type = "";
+        String defval = "";
+        Column column = field.getAnnotation(Column.class);
+        if (column != null) {
+            nullable = column.nullable();
+            unique = column.unique();
+            length = column.length();
+            type = column.type();
+            defval = column.defaultValue();
+        }
+
+        // create our SQL column definition
+        StringBuilder builder = new StringBuilder();
+        boolean typeDone = false;
+
+        // handle primary keyness
+        GeneratedValue genValue = fm.getGeneratedValue();
+        if (genValue != null) {
+            switch (genValue.strategy()) {
+            case AUTO:
+            case IDENTITY:
+                builder.append(" SERIAL UNIQUE");
+                typeDone = true;
+                break;
+            case SEQUENCE: // TODO
+                throw new IllegalArgumentException(
+                    "SEQUENCE key generation strategy not yet supported.");
+            case TABLE:
+                // nothing to do here, it'll be handled later
+                break;
+            }
+        }
+
+        if (!typeDone) {
+            if (type.length() == 0) {
+                type = getColumnType(fm);
+            }
+            builder.append(" ").append(type);
+
+            // if this is a VARCHAR field, add the length
+            if (type.equals("VARCHAR") || type.equals("VARBINARY")) {
+                builder.append("(").append(length).append(")");
+            }
+
+            // TODO: handle precision and scale
+
+            // handle nullability and uniqueness
+            if (!nullable) {
+                builder.append(" NOT NULL");
+            }
+            if (unique) {
+                builder.append(" UNIQUE");
+            }
+
+            // append the default value if one was specified
+            if (defval.length() > 0) {
+                builder.append(" DEFAULT ").append(defval);
+            }
+        }
+
+        return builder.toString();
+    }
+
+    /**
+     * Overridden by subclasses to create a dialect-specific {@link BuildVisitor}.
+     */
+    protected abstract BuildVisitor getBuildVisitor ();
+
+    /**
+     * Overridden by subclasses to create a dialect-specific {@link BindVisitor}.
+     */
+    protected abstract BindVisitor getBindVisitor (PreparedStatement stmt);
+
+    /**
+     * Overridden by subclasses to figure the dialect-specific SQL type of the given field.
+     */
+    protected abstract <T> String getColumnType (FieldMarshaller fm);
+
+    /** The class that maps persistent classes to marshallers. */
+    protected DepotTypes _types;
+
+    protected QueryClause _clause;
+    protected BuildVisitor _buildVisitor;
+    protected BindVisitor _bindVisitor;
+}

src/java/com/samskivert/jdbc/depot/SQLQueryBuilder.java

@@ -1,288 +0,0 @@
-//
-// $Id$
-//
-// samskivert library - useful routines for java programs
-// Copyright (C) 2006-2007 Michael Bayne, Pär Winzell
-// 
-// This library is free software; you can redistribute it and/or modify it
-// under the terms of the GNU Lesser General Public License as published
-// by the Free Software Foundation; either version 2.1 of the License, or
-// (at your option) any later version.
-//
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-// Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public
-// License along with this library; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-
-package com.samskivert.jdbc.depot;
-
-import java.sql.Connection;
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-import com.samskivert.io.PersistenceException;
-import com.samskivert.jdbc.depot.annotation.Computed;
-import com.samskivert.jdbc.depot.clause.FieldOverride;
-import com.samskivert.jdbc.depot.clause.ForUpdate;
-import com.samskivert.jdbc.depot.clause.FromOverride;
-import com.samskivert.jdbc.depot.clause.GroupBy;
-import com.samskivert.jdbc.depot.clause.Join;
-import com.samskivert.jdbc.depot.clause.Limit;
-import com.samskivert.jdbc.depot.clause.OrderBy;
-import com.samskivert.jdbc.depot.clause.QueryClause;
-import com.samskivert.jdbc.depot.clause.Where;
-
-/**
- * Builds actual SQL given a main persistent type and some {@link QueryClause} objects.
- */
-public class SQLQueryBuilder<T>
-{
-    /** The from override clause, if any. */
-    public FromOverride fromOverride;
-
-    /** The where clause. */
-    public Where where;
-
-    /** A list of join clauses, each potentially referencing a new class. */
-    public List<Join> joinClauses = new ArrayList<Join>();
-
-    /** The order by clause, if any. */
-    public OrderBy orderBy;
-
-    /** The group by clause, if any. */
-    public GroupBy groupBy;
-
-    /** The limit clause, if any. */
-    public Limit limit;
-
-    /** The For Update clause, if any. */
-    public ForUpdate forUpdate;
-
-    /**
-     * Constructs a {@link DepotTypes} object for your convenience given similar arguments used to
-     * construct a {@link SQLQueryBuilder}. This method mainly offloads the task of interrogating
-     * the various clauses for what persistent classes they introduce into the query.
-     */
-    public static <T> DepotTypes<T> getDepotTypes (
-        PersistenceContext ctx, Class<? extends PersistentRecord> type, QueryClause... clauses)
-        throws PersistenceException
-    {
-        Set<Class<? extends PersistentRecord>> classSet =
-            new HashSet<Class<? extends PersistentRecord>>();
-        if (type != null) {
-            classSet.add(type);
-        }
-
-        for (QueryClause clause : clauses) {
-            if (clause != null) {
-                clause.addClasses(classSet);
-            }
-        }
-
-        return new DepotTypes<T>(ctx, type, classSet);
-    }
-
-    /**
-     * Creates a new Query object to generate one or more instances of the specified persistent
-     * class, as dictated by the key and query clauses.  A persistence context is supplied for
-     * instantiation of marshallers, which may trigger table creations and schema migrations.
-     */
-    public SQLQueryBuilder (PersistenceContext ctx, DepotTypes<T> types, String[] fields,
-                            QueryClause... clauses)
-    {
-        _builder = new StringBuilder("select ");
-        _types = types;
-
-        // iterate over the clauses and sort them into the different types we understand
-        for (QueryClause clause : clauses) {
-            if (clause == null) {
-                continue;
-            }
-            if (clause instanceof Where) {
-                if (where != null) {
-                    throw new IllegalArgumentException(
-                        "Query can't contain multiple Where clauses.");
-                }
-                where = (Where) clause;
-
-            } else if (clause instanceof FromOverride) {
-                if (fromOverride != null) {
-                    throw new IllegalArgumentException(
-                        "Query can't contain multiple FromOverride clauses.");
-                }
-                fromOverride = (FromOverride) clause;
-
-            } else if (clause instanceof Join) {
-                joinClauses.add((Join) clause);
-
-            } else if (clause instanceof FieldOverride) {
-                _disMap.put(((FieldOverride) clause).getField(),
-                            ((FieldOverride) clause));
-
-            } else if (clause instanceof OrderBy) {
-                if (orderBy != null) {
-                    throw new IllegalArgumentException(
-                        "Query can't contain multiple OrderBy clauses.");
-                }
-                orderBy = (OrderBy) clause;
-
-            } else if (clause instanceof GroupBy) {
-                if (groupBy != null) {
-                    throw new IllegalArgumentException(
-                        "Query can't contain multiple GroupBy clauses.");
-                }
-                groupBy = (GroupBy) clause;
-
-            } else if (clause instanceof Limit) {
-                if (limit != null) {
-                    throw new IllegalArgumentException(
-                        "Query can't contain multiple Limit clauses.");
-                }
-                limit = (Limit) clause;
-
-            } else if (clause instanceof ForUpdate) {
-                if (forUpdate != null) {
-                    throw new IllegalArgumentException(
-                        "Query can't contain multiple For Update clauses.");
-                }
-                forUpdate = (ForUpdate) clause;
-            }
-        }
-
-        Computed entityComputed = _types.getMainType().getAnnotation(Computed.class);
-
-        // iterate over the fields we're filling in and figure out whence each one comes
-        boolean skip = true;
-        for (String field : fields) {
-            if (!skip) {
-                _builder.append(", ");
-            }
-            skip = false;
-
-            // first, see if there's a field override
-            FieldOverride clause1 = _disMap.get(field);
-            if (clause1 != null) {
-                clause1.appendClause(_types, _builder);
-                continue;
-            }
-
-            // figure out the class we're selecting from unless we're otherwise overriden:
-            // for a concrete record, simply use the corresponding table; for a computed one,
-            // default to the shadowed concrete record, or null if there isn't one
-            Class<? extends PersistentRecord> tableClass =
-                entityComputed == null ? _types.getMainType() : entityComputed.shadowOf();
-
-            // handle the field-level @Computed annotation, if there is one
-            Computed fieldComputed =
-                _types.getMainMarshaller().getFieldMarshaller(field).getComputed();
-            if (fieldComputed != null) {
-                // check if the computed field has a literal SQL definition
-                if (fieldComputed.fieldDefinition().length() > 0) {
-                    _builder.append(fieldComputed.fieldDefinition()).append(" as ").append(field);
-                    continue;
-                }
-
-                // or if we can simply ignore the field
-                if (!fieldComputed.required()) {
-                    skip = true;
-                    continue;
-                }
-
-                // else see if there's an overriding shadowOf definition
-                if (fieldComputed.shadowOf() != null) {
-                    tableClass = fieldComputed.shadowOf();
-                }
-            }
-
-            // if we get this far we hopefully have a table to select from
-            if (tableClass != null) {
-                String tableName = _types.getTableAbbreviation(tableClass);
-                _builder.append(tableName).append(".").append(field);
-                continue;
-            }
-
-            // else owie
-            throw new IllegalArgumentException(
-                "Persistent field has no definition [class=" + _types.getMainType() +
-                ", field=" + field + "]");
-        }
-    }
-
-    public PreparedStatement prepare (Connection conn)
-        throws SQLException
-    {
-        if (fromOverride != null) {
-            fromOverride.appendClause(_types, _builder);
-
-        } else if (_types.getMainTableName() != null) {
-            _builder.append(" from ").append(_types.getMainTableName()).
-                append(" as ").append(_types.getMainTableAbbreviation());
-
-        } else {
-            throw new SQLException("Query on @Computed entity with no FromOverrideClause.");
-        }
-
-        for (Join clause : joinClauses) {
-            clause.appendClause(_types, _builder);
-        }
-        if (where != null) {
-            where.appendClause(_types, _builder);
-        }
-        if (groupBy != null) {
-            groupBy.appendClause(_types, _builder);
-        }
-        if (orderBy != null) {
-            orderBy.appendClause(_types, _builder);
-        }
-        if (limit != null) {
-            limit.appendClause(_types, _builder);
-        }
-        if (forUpdate != null) {
-            forUpdate.appendClause(_types, _builder);
-        }
-
-        PreparedStatement pstmt = conn.prepareStatement(_builder.toString());
-        int argIdx = 1;
-        for (Join clause : joinClauses) {
-            argIdx = clause.bindClauseArguments(pstmt, argIdx);
-        }
-        if (where != null) {
-            argIdx = where.bindClauseArguments(pstmt, argIdx);
-        }
-        if (groupBy != null) {
-            argIdx = groupBy.bindClauseArguments(pstmt, argIdx);
-        }
-        if (orderBy != null) {
-            argIdx = orderBy.bindClauseArguments(pstmt, argIdx);
-        }
-        if (limit != null) {
-            argIdx = limit.bindClauseArguments(pstmt, argIdx);
-        }
-        if (forUpdate != null) {
-            argIdx = forUpdate.bindClauseArguments(pstmt, argIdx);
-        }
-
-        return pstmt;
-    }
-
-    /** A StringBuilder to hold the constructed SQL. */
-    protected StringBuilder _builder;
-
-    /** The class that maps persistent classes to marshallers. */
-    protected DepotTypes<T> _types;
-
-    /** Persistent class fields mapped to field override clauses. */
-    protected Map<String, FieldOverride> _disMap = new HashMap<String, FieldOverride>();
-}

src/java/com/samskivert/jdbc/depot/TableKeyGenerator.java

@@ -25,23 +25,25 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
+import com.samskivert.jdbc.depot.annotation.GeneratedValue;
 import com.samskivert.jdbc.depot.annotation.TableGenerator;
 
+import com.samskivert.jdbc.DatabaseLiaison;
 import com.samskivert.jdbc.JDBCUtil;
+import com.samskivert.jdbc.LiaisonRegistry;
 
 /**
- * Generates primary keys using an external table 
+ * Generates primary keys using an external table .
  */
-public class TableKeyGenerator implements KeyGenerator
+public class TableKeyGenerator extends KeyGenerator
 {
-    public TableKeyGenerator (TableGenerator annotation)
+    public TableKeyGenerator (TableGenerator tg, GeneratedValue gv, String table, String column)
     {
-        _table = defStr(annotation.table(), "IdSequences");
-        _pkColumnName = defStr(annotation.pkColumnName(), "sequence");
-        _pkColumnValue = defStr(annotation.pkColumnValue(), "default");
-        _valueColumnName = defStr(annotation.valueColumnName(), "value");
-        _allocationSize = annotation.allocationSize();
-        _initialValue = annotation.initialValue();
+        super(gv, table, column);
+        _valueTable = defStr(tg.table(), "IdSequences");
+        _pkColumnName = defStr(tg.pkColumnName(), "sequence");
+        _pkColumnValue = defStr(tg.pkColumnValue(), "default");
+        _valueColumnName = defStr(tg.valueColumnName(), "value");
     }
 
     // from interface KeyGenerator
@@ -51,20 +53,23 @@ public class TableKeyGenerator implements KeyGenerator
     }
 
     // from interface KeyGenerator
-    public void init (Connection conn)
+    public void init (Connection conn, DatabaseLiaison liaison)
         throws SQLException
     {
         // make sure our table exists
-        JDBCUtil.createTableIfMissing(conn, _table, new String[] {
-            _pkColumnName + " VARCHAR(255) PRIMARY KEY",
-            _valueColumnName + " INTEGER NOT NULL"
-        }, "");
+        liaison.createTableIfMissing(
+            conn, _valueTable,
+            new String[] { _pkColumnName, _valueColumnName },
+            new String[] { "VARCHAR(255)", "INTEGER NOT NULL" },
+            null,
+            new String[] { _pkColumnName });
 
         // and also that there's a row in it for us
         PreparedStatement stmt = null;
         try {
             stmt = conn.prepareStatement(
-                "SELECT * FROM " + _table + " WHERE " + _pkColumnName + " = ?");
+                " SELECT * FROM " + liaison.tableSQL(_valueTable) +
+                "  WHERE " + liaison.columnSQL(_pkColumnName) + " = ?");
             stmt.setString(1, _pkColumnValue);
             if (stmt.executeQuery().next()) {
                 return;
@@ -72,8 +77,10 @@ public class TableKeyGenerator implements KeyGenerator
 
             JDBCUtil.close(stmt);
             stmt = null;
-            stmt = conn.prepareStatement("INSERT INTO " + _table + " SET " +
-                                         _pkColumnName + " = ?, " + _valueColumnName + " = ?");
+            stmt = conn.prepareStatement(
+                " INSERT INTO " + liaison.tableSQL(_valueTable) + " (" +
+                liaison.columnSQL(_pkColumnName) + ", " + liaison.columnSQL(_valueColumnName) +
+                ") VALUES (?, ?)");
             stmt.setString(1, _pkColumnValue);
             stmt.setInt(2, _initialValue);
             stmt.executeUpdate();
@@ -84,27 +91,32 @@ public class TableKeyGenerator implements KeyGenerator
     }
 
     // from interface KeyGenerator
-    public int nextGeneratedValue (Connection conn)
+    public int nextGeneratedValue (Connection conn, DatabaseLiaison liaison)
         throws SQLException
     {
         PreparedStatement stmt = null;
         try {
-            String query = "SELECT " + _valueColumnName + " FROM " + _table +
-                " WHERE " + _pkColumnName + "= ? FOR UPDATE";
+            // TODO: Make this lockless!
+            String query =
+                " SELECT " + liaison.columnSQL(_valueColumnName) +
+                "   FROM " + liaison.tableSQL(_valueTable) +
+                "  WHERE " + liaison.columnSQL(_pkColumnName) + " = ? FOR UPDATE";
             stmt = conn.prepareStatement(query);
             stmt.setString(1, _pkColumnValue);
 
             ResultSet rs = stmt.executeQuery();
             if (!rs.next()) {
-                throw new SQLException("Failed to find next primary key value [table=" + _table +
-                                       ", column=" + _valueColumnName +
+                throw new SQLException("Failed to find next primary key value " +
+                                       "[table=" + _valueTable + ", column=" + _valueColumnName +
                                        ", where=" + _pkColumnName + "=" + _pkColumnValue + "]");
             }
             int val = rs.getInt(1);
             JDBCUtil.close(stmt);
 
-            stmt = conn.prepareStatement("UPDATE " + _table + " SET " + _valueColumnName + " = ? " +
-                                         "WHERE " + _pkColumnName + " = ?");
+            stmt = conn.prepareStatement(
+                " UPDATE " + liaison.tableSQL(_valueTable) +
+                "    SET " + liaison.columnSQL(_valueColumnName) + " = ? " +
+                "  WHERE " + liaison.columnSQL(_pkColumnName) + " = ?");
             stmt.setInt(1, val + _allocationSize);
             stmt.setString(2, _pkColumnValue);
             stmt.executeUpdate();
@@ -126,10 +138,8 @@ public class TableKeyGenerator implements KeyGenerator
         return value;
     }
 
-    protected String _table;
+    protected String _valueTable;
     protected String _pkColumnName;
     protected String _pkColumnValue;
     protected String _valueColumnName;
-    protected int _initialValue;
-    protected int _allocationSize;
 }

src/java/com/samskivert/jdbc/depot/WhereClause.java

@@ -18,3 +18,13 @@
 // License along with this library; if not, write to the Free Software
 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 
+package com.samskivert.jdbc.depot;
+
+import com.samskivert.jdbc.depot.clause.QueryClause;
+
+/**
+ * Currently only exists as a type without any functionality of its own.
+ */
+public abstract class WhereClause extends QueryClause
+{
+}

src/java/com/samskivert/jdbc/depot/annotation/Column.java

@@ -53,10 +53,9 @@ public @interface Column
     boolean nullable () default false;
 
     /**
-     * The SQL fragment that is used when generating the DDL for the column. Defaults to the
-     * generated SQL to create a column of the inferred type.
+     * The SQL type that is used when generating the DDL for the column.
      */
-    String columnDefinition () default ""; 
+    String type() default "";
 
     /**
      * The column length. (Applies to String and byte[] columns.)

src/java/com/samskivert/jdbc/depot/annotation/Computed.java

@@ -25,13 +25,11 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
 
 /**
  * Marks a field as computed, meaning it is ignored for schema purposes and it does not directly
- * correspond to a column in a table, thus its value must be overridden in the {@link
- * QueryBuilderContext}.
+ * correspond to a column in a table.
  */
 @Retention(value=RetentionPolicy.RUNTIME)
 @Target({ ElementType.FIELD, ElementType.TYPE })

src/java/com/samskivert/jdbc/depot/annotation/Entity.java

@@ -37,8 +37,4 @@ public @interface Entity
 
     /** Defines indices to add to this entity's table. */
     Index[] indices () default {};
-
-    /** Additional SQL to be added when creating this entity's table for the first time. You can
-     * specify a MySQL table storage type for example. */
-    String postamble () default "";
 }

src/java/com/samskivert/jdbc/depot/annotation/GeneratedValue.java

@@ -40,4 +40,18 @@ public @interface GeneratedValue
 
     /** Identifies the strategy to be used to generate this value. */
     GenerationType strategy () default GenerationType.AUTO;
+
+    /**
+     * The initial value to be used when allocating id numbers from the generator. The default
+     * initial value is 1. <em>Note:</em> this default differs from the value used by the EJB3
+     * persistence framework.
+     */
+    int initialValue () default 1;
+
+    /**
+     * The amount to increment by when allocating id numbers from the generator. The default
+     * allocation size is 1. <em>Note:</em> this default differs from the value used by the EJB3
+     * persistence framework.
+     */
+    int allocationSize () default 1;
 }

src/java/com/samskivert/jdbc/depot/annotation/TableGenerator.java

@@ -63,18 +63,4 @@ public @interface TableGenerator
      * the primary key column of the generator table
      */    
     String pkColumnValue () default "";
-
-    /**
-     * The initial value to be used when allocating id numbers from the generator. The default
-     * initial value is 1. <em>Note:</em> this default differs from the value used by the EJB3
-     * persistence framework.
-     */
-    int initialValue () default 1;
-
-    /**
-     * The amount to increment by when allocating id numbers from the generator. The default
-     * allocation size is 1. <em>Note:</em> this default differs from the value used by the EJB3
-     * persistence framework.
-     */
-    int allocationSize () default 1;
 }

src/java/com/samskivert/jdbc/depot/clause/DeleteClause.java

@@ -0,0 +1,67 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot.clause;
+
+import java.util.Collection;
+
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.WhereClause;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
+
+/**
+ * Builds actual SQL given a main persistent type and some {@link QueryClause} objects.
+ */
+public class DeleteClause<T extends PersistentRecord> extends QueryClause
+{
+    public DeleteClause (Class<? extends PersistentRecord> pClass, WhereClause where)
+    {
+        _pClass = pClass;
+        _where = where;
+    }
+
+    public Class<? extends PersistentRecord> getPersistentClass ()
+    {
+        return _pClass;
+    }
+
+    public WhereClause getWhereClause ()
+    {
+        return _where;
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        classSet.add(_pClass);
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    /** The type of persistent record on which we operate. */
+    protected Class<? extends PersistentRecord> _pClass;
+
+    /** The where clause. */
+    protected WhereClause _where;
+}

src/java/com/samskivert/jdbc/depot/clause/FieldOverride.java

@@ -20,14 +20,12 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
 import com.samskivert.io.PersistenceException;
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
 import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.LiteralExp;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 
@@ -68,11 +66,22 @@ public class FieldOverride extends QueryClause
         return _field;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    public SQLExpression getOverride ()
     {
-        _override.appendExpression(query, builder);
-        builder.append(" as ").append(_field);
+        return _override;
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        _override.addClasses(classSet);
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor visitor)
+        throws Exception
+    {
+        visitor.visit(this); 
     }
 
     /** The name of the field on the persistent object to override. */
@@ -80,4 +89,5 @@ public class FieldOverride extends QueryClause
 
     /** The overriding expression. */
     protected SQLExpression _override;
+
 }

src/java/com/samskivert/jdbc/depot/clause/ForUpdate.java

@@ -20,21 +20,24 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 
 /**
  *  Represents a FOR UPDATE clause.
  */
 public class ForUpdate extends QueryClause
 {
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        builder.append(" for update ");
     }
 }

src/java/com/samskivert/jdbc/depot/clause/FromOverride.java

@@ -20,14 +20,13 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
 
 import com.samskivert.io.PersistenceException;
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 
 /**
  *  Completely overrides the FROM clause, if it exists.
@@ -54,27 +53,25 @@ public class FromOverride extends QueryClause
         _fromClasses.addAll(fromClasses);
     }
 
-    // from QueryClause
-    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    public List<Class<? extends PersistentRecord>> getFromClasses ()
     {
-        classSet.addAll(_fromClasses);
+        return _fromClasses;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        builder.append(" from " );
-        for (int ii = 0; ii < _fromClasses.size(); ii++) {
-            if (ii > 0) {
-                builder.append(", ");
-            }
-            builder.append(query.getTableName(_fromClasses.get(ii))).
-                append(" as ").append(query.getTableAbbreviation(_fromClasses.get(ii)));
+        classSet.addAll(getFromClasses());
     }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder)
+        throws Exception
+    {
+        builder.visit(this);
     }
 
     /** The classes of the tables we're selecting from. */
-    protected ArrayList<Class<? extends PersistentRecord>> _fromClasses =
+    protected List<Class<? extends PersistentRecord>> _fromClasses =
         new ArrayList<Class<? extends PersistentRecord>>();
-
 }

src/java/com/samskivert/jdbc/depot/clause/GroupBy.java

@@ -20,12 +20,10 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 
 /**
@@ -38,28 +36,24 @@ public class GroupBy extends QueryClause
         _values = values;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    public SQLExpression[] getValues ()
     {
-        builder.append(" group by ");
-        for (int ii = 0; ii < _values.length; ii++) {
-            if (ii > 0) {
-                builder.append(", ");
-            }
-            _values[ii].appendExpression(query, builder);
-        }
+        return _values;
     }
 
-    // from QueryClause
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
     {
-        for (int ii = 0; ii < _values.length; ii++) {
-            argIdx = _values[ii].bindExpressionArguments(pstmt, argIdx);
+        builder.visit(this);
     }
-        return argIdx;
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        // I can't imagine a GROUP BY clause bringing in new tables... ?
     }
 
     /** The expressions that are generated for the clause. */
     protected SQLExpression[] _values;
+
 }

src/java/com/samskivert/jdbc/depot/clause/InsertClause.java

@@ -0,0 +1,74 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot.clause;
+
+import java.util.Collection;
+
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
+
+/**
+ * Builds actual SQL given a main persistent type and some {@link QueryClause} objects.
+ */
+public class InsertClause<T extends PersistentRecord> extends QueryClause
+{
+    public InsertClause (Class<? extends PersistentRecord> pClass, Object pojo, String ixField)
+    {
+        _pClass = pClass;
+        _pojo = pojo;
+        _ixField = ixField;
+    }
+
+    public Class<? extends PersistentRecord> getPersistentClass ()
+    {
+        return _pClass;
+    }
+
+    public Object getPojo ()
+    {
+        return _pojo;
+    }
+
+    public String getIndexField ()
+    {
+        return _ixField;
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        classSet.add(_pClass);
+        // If we add SQLExpression[] values INSERT, remember to recurse into them here.
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    protected Class<? extends PersistentRecord> _pClass;
+
+    /** The object from which to fetch values, or null. */
+    protected Object _pojo;
+
+    protected String _ixField;
+}

src/java/com/samskivert/jdbc/depot/clause/Join.java

@@ -20,16 +20,14 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
 import com.samskivert.io.PersistenceException;
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
 import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
-import com.samskivert.jdbc.depot.operator.Conditionals.*;
+import com.samskivert.jdbc.depot.operator.Conditionals.Equals;
 
 /**
  *  Represents a JOIN.
@@ -50,7 +48,7 @@ public class Join extends QueryClause
     public Join (ColumnExp primary, ColumnExp join)
         throws PersistenceException
     {
-        _joinClass = join.pClass;
+        _joinClass = join.getPersistentClass();
         _joinCondition = new Equals(primary, join);
     }
 
@@ -60,12 +58,6 @@ public class Join extends QueryClause
         _joinCondition = joinCondition;
     }
 
-    // from QueryClause
-    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
-    {
-        classSet.add(_joinClass);
-    }
-
     /**
      * Configures the type of join to be performed.
      */
@@ -75,30 +67,31 @@ public class Join extends QueryClause
         return this;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    public Type getType ()
     {
-        switch (_type) {
-        case INNER:
-            builder.append(" inner join " );
-            break;
-        case LEFT_OUTER:
-            builder.append(" left outer join " );
-            break;
-        case RIGHT_OUTER:
-            builder.append(" right outer join " );
-            break;
-        }
-        builder.append(query.getTableName(_joinClass)).append(" as ");
-        builder.append(query.getTableAbbreviation(_joinClass)).append(" on ");
-        _joinCondition.appendExpression(query, builder);
+        return _type;
     }
 
-    // from QueryClause
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public Class<? extends PersistentRecord> getJoinClass ()
     {
-        return _joinCondition.bindExpressionArguments(pstmt, argIdx);
+        return _joinClass;
+    }
+
+    public SQLExpression getJoinCondition ()
+    {
+        return _joinCondition;
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        classSet.add(_joinClass);
     }
 
     /** Indicates the type of join to be performed. */

src/java/com/samskivert/jdbc/depot/clause/Limit.java

@@ -20,12 +20,10 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 
 /**
  *  Represents a LIMIT/OFFSET clause, for pagination.
@@ -38,19 +36,25 @@ public class Limit extends QueryClause
         _count = count;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    public int getOffset ()
     {
-        builder.append(" limit ? offset ? ");
+        return _offset;
     }
     
-    // from QueryClause
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public int getCount ()
+    {
+        return _count;
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+    
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        pstmt.setObject(argIdx++, _count);
-        pstmt.setObject(argIdx++, _offset);
-        return argIdx;
     }
     
     /** The first row of the result set to return. */

src/java/com/samskivert/jdbc/depot/clause/OrderBy.java

@@ -20,13 +20,10 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
-import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.LiteralExp;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 
@@ -46,22 +43,6 @@ public class OrderBy extends QueryClause
         return ascending(new LiteralExp("rand()"));
     }
 
-    /**
-     * Creates and returns an ascending order by clause on the supplied column.
-     */
-    public static OrderBy ascending (String column)
-    {
-        return ascending(new ColumnExp(null, column));
-    }
-
-    /**
-     * Creates and returns a descending order by clause on the supplied column.
-     */
-    public static OrderBy descending (String column)
-    {
-        return descending(new ColumnExp(null, column));
-    }
-
     /**
      * Creates and returns an ascending order by clause on the supplied expression.
      */
@@ -84,27 +65,28 @@ public class OrderBy extends QueryClause
         _orders = orders;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    public SQLExpression[] getValues ()
     {
-        builder.append(" order by ");
-        for (int ii = 0; ii < _values.length; ii++) {
-            if (ii > 0) {
-                builder.append(", ");
-            }
-            _values[ii].appendExpression(query, builder);
-            builder.append(" ").append(_orders[ii]);
-        }
+        return _values;
     }
     
-    // from QueryClause
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public Order[] getOrders ()
     {
-        for (int ii = 0; ii < _values.length; ii++) {
-            argIdx = _values[ii].bindExpressionArguments(pstmt, argIdx);
+        return _orders;
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        for (SQLExpression expression : _values) {
+            expression.addClasses(classSet);
         }
-        return argIdx;
     }
     
     /** The expressions that are generated for the clause. */
@@ -112,4 +94,5 @@ public class OrderBy extends QueryClause
 
     /** Whether the ordering is to be ascending or descending. */
     protected Order[] _orders;
+
 }

src/java/com/samskivert/jdbc/depot/clause/QueryClause.java

@@ -20,39 +20,11 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
-import java.util.Collection;
-
-import com.samskivert.jdbc.depot.QueryBuilderContext;
-import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.SQLExpression;
 
 /**
  * Represents a piece or modifier of an SQL query.
  */
-public abstract class QueryClause
+public abstract class QueryClause implements SQLExpression
 {
-    /**
-     * Adds all persistent classes referenced by this clause, if any, to the supplied set.
-     */
-    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
-    {
-    }
-
-    /**
-     * Constructs the SQL form of this query clause. The implementor is expected to call methods on
-     * the Query object to e.g. resolve current table abbreviations associated with classes.
-     */
-    public abstract void appendClause (QueryBuilderContext<?> query, StringBuilder builder);
-
-    /**
-     * Binds any objects that were referenced in the generated SQL.  For each ? that appears in the
-     * SQL, precisely one parameter must be claimed and bound in this method, and argIdx
-     * incremented and returned. The default implementation binds nothing.
-     */
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
-    {
-        return argIdx;
-    }
 }

src/java/com/samskivert/jdbc/depot/clause/SelectClause.java

@@ -0,0 +1,212 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot.clause;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.WhereClause;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
+
+/**
+ * Builds actual SQL given a main persistent type and some {@link QueryClause} objects.
+ */
+public class SelectClause<T extends PersistentRecord> extends QueryClause
+{
+    /**
+     * Creates a new Query object to generate one or more instances of the specified persistent
+     * class, as dictated by the key and query clauses.  A persistence context is supplied for
+     * instantiation of marshallers, which may trigger table creations and schema migrations.
+     */
+    public SelectClause (Class<T> pClass, String[] fields, QueryClause... clauses)
+    {
+        _pClass = pClass;
+        _fields = fields;
+
+        // iterate over the clauses and sort them into the different types we understand
+        for (QueryClause clause : clauses) {
+            if (clause == null) {
+                continue;
+            }
+            if (clause instanceof WhereClause) {
+                if (_where != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple Where clauses.");
+                }
+                _where = (WhereClause) clause;
+
+            } else if (clause instanceof FromOverride) {
+                if (_fromOverride != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple FromOverride clauses.");
+                }
+                _fromOverride = (FromOverride) clause;
+
+            } else if (clause instanceof Join) {
+                _joinClauses.add((Join) clause);
+
+            } else if (clause instanceof FieldOverride) {
+                _disMap.put(((FieldOverride) clause).getField(), ((FieldOverride) clause));
+
+            } else if (clause instanceof OrderBy) {
+                if (_orderBy != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple OrderBy clauses.");
+                }
+                _orderBy = (OrderBy) clause;
+
+            } else if (clause instanceof GroupBy) {
+                if (_groupBy != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple GroupBy clauses.");
+                }
+                _groupBy = (GroupBy) clause;
+
+            } else if (clause instanceof Limit) {
+                if (_limit != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple Limit clauses.");
+                }
+                _limit = (Limit) clause;
+
+            } else if (clause instanceof ForUpdate) {
+                if (_forUpdate != null) {
+                    throw new IllegalArgumentException(
+                        "Query can't contain multiple For Update clauses.");
+                }
+                _forUpdate = (ForUpdate) clause;
+            }
+        }
+    }
+
+    public FieldOverride lookupOverride (String field)
+    {
+        return _disMap.get(field);
+    }
+
+    public Collection<FieldOverride> getFieldOverrides ()
+    {
+        return _disMap.values();
+    }
+
+    public Class<T> getPersistentClass ()
+    {
+        return _pClass;
+    }
+
+    public String[] getFields ()
+    {
+        return _fields;
+    }
+
+    public FromOverride getFromOverride ()
+    {
+        return _fromOverride;
+    }
+
+    public WhereClause getWhereClause ()
+    {
+        return _where;
+    }
+
+    public List<Join> getJoinClauses ()
+    {
+        return _joinClauses;
+    }
+
+    public OrderBy getOrderBy ()
+    {
+        return _orderBy;
+    }
+
+    public GroupBy getGroupBy ()
+    {
+        return _groupBy;
+    }
+
+    public Limit getLimit ()
+    {
+        return _limit;
+    }
+
+    public ForUpdate getForUpdate ()
+    {
+        return _forUpdate;
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        classSet.add(_pClass);
+        if (_fromOverride != null) {
+            _fromOverride.addClasses(classSet);
+        }
+        if (_where != null) {
+            _where.addClasses(classSet);
+        }
+        for (Join join : _joinClauses) {
+            join.addClasses(classSet);
+        }
+        for (FieldOverride override : _disMap.values()) {
+            override.addClasses(classSet);
+        }
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    /** Persistent class fields mapped to field override clauses. */
+    protected Map<String, FieldOverride> _disMap = new HashMap<String, FieldOverride>();
+
+    /** The persistent class this select defines. */
+    protected Class<T> _pClass;
+
+    /** The persistent fields to select. */
+    protected String[] _fields;
+
+    /** The from override clause, if any. */
+    protected FromOverride _fromOverride;
+
+    /** The where clause. */
+    protected WhereClause _where;
+
+    /** A list of join clauses, each potentially referencing a new class. */
+    protected List<Join> _joinClauses = new ArrayList<Join>();
+
+    /** The order by clause, if any. */
+    protected OrderBy _orderBy;
+
+    /** The group by clause, if any. */
+    protected GroupBy _groupBy;
+
+    /** The limit clause, if any. */
+    protected Limit _limit;
+
+    /** The For Update clause, if any. */
+    protected ForUpdate _forUpdate;
+}

src/java/com/samskivert/jdbc/depot/clause/UpdateClause.java

@@ -0,0 +1,114 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot.clause;
+
+import java.util.Collection;
+
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.WhereClause;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
+import com.samskivert.jdbc.depot.expression.SQLExpression;
+
+/**
+ * Builds actual SQL given a main persistent type and some {@link QueryClause} objects.
+ */
+public class UpdateClause<T extends PersistentRecord> extends QueryClause
+{
+    public UpdateClause (Class<? extends PersistentRecord> pClass, WhereClause where,
+                         String[] fields, T pojo)
+    {
+        _pClass = pClass;
+        _where = where;
+        _fields = fields;
+        _values = null;
+        _pojo = pojo;
+    }
+    
+    public UpdateClause (Class<? extends PersistentRecord> pClass, WhereClause where,
+                         String[] fields, SQLExpression[] values)
+    {
+        _pClass = pClass;
+        _fields = fields;
+        _where = where;
+        _values = values;
+        _pojo = null;
+    }
+    
+    public WhereClause getWhereClause ()
+    {
+        return _where;
+    }
+
+    public String[] getFields ()
+    {
+        return _fields;
+    }
+
+    public SQLExpression[] getValues ()
+    {
+        return _values;
+    }
+
+    public Object getPojo ()
+    {
+        return _pojo;
+    }
+
+    public Class<? extends PersistentRecord> getPersistentClass ()
+    {
+        return _pClass;
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        classSet.add(_pClass);
+        if (_where != null) {
+            _where.addClasses(classSet);
+        }
+        if (_values != null) {
+            for (int ii = 0; ii < _values.length; ii ++) {
+                _values[ii].addClasses(classSet);
+            }
+        }
+    }
+
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
+    {
+        builder.visit(this);
+    }
+
+    /** The class we're updating. */
+    protected Class<? extends PersistentRecord> _pClass;
+
+    /** The where clause. */
+    protected WhereClause _where;
+
+    /** The persistent fields to update. */
+    protected String[] _fields;
+    
+    /** The field values, or null. */
+    protected SQLExpression[] _values;
+    
+    /** The object from which to fetch values, or null. */
+    protected Object _pojo;
+}

src/java/com/samskivert/jdbc/depot/clause/Where.java

@@ -20,14 +20,12 @@
 
 package com.samskivert.jdbc.depot.clause;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
-import com.samskivert.jdbc.depot.clause.QueryClause;
+import com.samskivert.jdbc.depot.WhereClause;
 import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 import com.samskivert.jdbc.depot.expression.ValueExp;
 import com.samskivert.jdbc.depot.operator.Conditionals.Equals;
@@ -38,13 +36,8 @@ import com.samskivert.jdbc.depot.operator.Logic.And;
  * Represents a where clause: the condition can be any comparison operator or logical combination
  * thereof.
  */
-public class Where extends QueryClause
+public class Where extends WhereClause
 {
-    public Where (String index, Comparable value)
-    {
-        this(new ColumnExp(index), value);
-    }
-
     public Where (ColumnExp column, Comparable value)
     {
         this(new ColumnExp[] { column }, new Comparable[] { value });
@@ -64,18 +57,6 @@ public class Where extends QueryClause
              new Comparable[] { value1, value2, value3 });
     }
 
-    public Where (String index1, Comparable value1, String index2, Comparable value2)
-    {
-        this(new ColumnExp(index1), value1, new ColumnExp(index2), value2);
-    }
-
-    public Where (String index1, Comparable value1, String index2, Comparable value2,
-                String index3, Comparable value3)
-    {
-        this(new ColumnExp(index1), value1, new ColumnExp(index2), value2, 
-             new ColumnExp(index3), value3);
-    }
-
     public Where (ColumnExp[] columns, Comparable[] values)
     {
         this(toCondition(columns, values));
@@ -86,18 +67,21 @@ public class Where extends QueryClause
         _condition = condition;
     }
 
-    // from QueryClause
-    public void appendClause (QueryBuilderContext<?> query, StringBuilder builder)
+    public SQLExpression getCondition ()
     {
-        builder.append(" where ");
-        _condition.appendExpression(query, builder);
+        return _condition;
     }
 
-    // from QueryClause
-    public int bindClauseArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    // from SQLExpression
+    public void accept (ExpressionVisitor builder) throws Exception
     {
-        return _condition.bindExpressionArguments(pstmt, argIdx);
+        builder.visit(this);
+    }
+
+    // from SQLExpression
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+    {
+        _condition.addClasses(classSet);
     }
     
     protected static SQLExpression toCondition (ColumnExp[] columns, Comparable[] values)

src/java/com/samskivert/jdbc/depot/expression/ColumnExp.java

@@ -20,53 +20,48 @@
 
 package com.samskivert.jdbc.depot.expression;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
 
 /**
- * An expression identifying a column of a class, e.g. GameRecord.itemId. If no class is given,
- * no disambiguation occurs in the generated SQL.
+ * An expression that unambiguously identifies a field of a class, e.g. GameRecord.itemId.
  */
 public class ColumnExp
     implements SQLExpression
 {
-    /** The table that hosts the column we reference, or null. */
-    final public Class<? extends PersistentRecord> pClass;
-
-    /** The name of the column we reference. */
-    final public String pColumn;
-
-    public ColumnExp (String column)
-    {
-        this(null, column);
-    }
-
-    public ColumnExp (Class<? extends PersistentRecord> c, String column)
+    public ColumnExp (Class<? extends PersistentRecord> pClass, String field)
     {
         super();
-        pClass = c;
-        this.pColumn = column;
+        _pClass = pClass;
+        _pField = field;
     }
 
     // from SQLExpression
-    public void appendExpression (QueryBuilderContext<?> query, StringBuilder builder)
+    public void accept (ExpressionVisitor builder) throws Exception
     {
-        if (pClass == null || query == null) {
-            builder.append(pColumn);
-        } else {
-            String tRef = query.getTableAbbreviation(pClass);
-            builder.append(tRef).append(".").append(pColumn);
-        }
+        builder.visit(this);
     }
 
     // from SQLExpression
-    public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        return argIdx;
+        classSet.add(_pClass);
     }
 
+    public Class<? extends PersistentRecord> getPersistentClass ()
+    {
+        return _pClass;
+    }
+
+    public String getField ()
+    {
+        return _pField;
+    }
+
+    /** The table that hosts the column we reference, or null. */
+    protected final Class<? extends PersistentRecord> _pClass;
+
+    /** The name of the column we reference. */
+    protected final String _pField;
 }

src/java/com/samskivert/jdbc/depot/expression/ExpressionVisitor.java

@@ -0,0 +1,103 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne, Pär Winzell
+//
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.jdbc.depot.expression;
+
+import com.samskivert.jdbc.depot.Key.WhereCondition;
+import com.samskivert.jdbc.depot.Key;
+import com.samskivert.jdbc.depot.MultiKey;
+import com.samskivert.jdbc.depot.PersistentRecord;
+
+import com.samskivert.jdbc.depot.clause.DeleteClause;
+import com.samskivert.jdbc.depot.clause.FieldOverride;
+import com.samskivert.jdbc.depot.clause.ForUpdate;
+import com.samskivert.jdbc.depot.clause.FromOverride;
+import com.samskivert.jdbc.depot.clause.GroupBy;
+import com.samskivert.jdbc.depot.clause.InsertClause;
+import com.samskivert.jdbc.depot.clause.Join;
+import com.samskivert.jdbc.depot.clause.Limit;
+import com.samskivert.jdbc.depot.clause.OrderBy;
+import com.samskivert.jdbc.depot.clause.SelectClause;
+import com.samskivert.jdbc.depot.clause.UpdateClause;
+import com.samskivert.jdbc.depot.clause.Where;
+
+import com.samskivert.jdbc.depot.operator.Conditionals.In;
+import com.samskivert.jdbc.depot.operator.Conditionals.IsNull;
+import com.samskivert.jdbc.depot.operator.Conditionals.Match;
+import com.samskivert.jdbc.depot.operator.Logic.Not;
+import com.samskivert.jdbc.depot.operator.SQLOperator.BinaryOperator;
+import com.samskivert.jdbc.depot.operator.SQLOperator.MultiOperator;
+
+/**
+ * Enumerates visitation methods for every possible SQL expression type.
+ */
+public interface ExpressionVisitor
+{
+    public void visit (FieldOverride fieldOverride)
+        throws Exception;
+    public void visit (WhereCondition<? extends PersistentRecord> whereCondition)
+        throws Exception;
+    public void visit (Key key)
+        throws Exception;
+    public void visit (MultiKey<? extends PersistentRecord> key)
+        throws Exception;
+    public void visit (FunctionExp functionExp)
+        throws Exception;
+    public void visit (FromOverride fromOverride)
+        throws Exception;
+    public void visit (MultiOperator multiOperator)
+        throws Exception;
+    public void visit (BinaryOperator binaryOperator)
+        throws Exception;
+    public void visit (IsNull isNull)
+        throws Exception;
+    public void visit (In in)
+        throws Exception;
+    public void visit (Match match)
+        throws Exception;
+    public void visit (ColumnExp columnExp)
+        throws Exception;
+    public void visit (Not not)
+        throws Exception;
+    public void visit (GroupBy groupBy)
+        throws Exception;
+    public void visit (ForUpdate forUpdate)
+        throws Exception;
+    public void visit (OrderBy orderBy)
+        throws Exception;
+    public void visit (Where where)
+        throws Exception;
+    public void visit (Join join)
+        throws Exception;
+    public void visit (Limit limit)
+        throws Exception;
+    public void visit (LiteralExp literalExp)
+        throws Exception;
+    public void visit (ValueExp valueExp)
+        throws Exception;
+    public void visit (SelectClause<? extends PersistentRecord> selectClause)
+        throws Exception;
+    public void visit (UpdateClause<? extends PersistentRecord> updateClause)
+        throws Exception;
+    public void visit (DeleteClause<? extends PersistentRecord> deleteClause)
+        throws Exception;
+    public void visit (InsertClause<? extends PersistentRecord> insertClause)
+        throws Exception;
+}

src/java/com/samskivert/jdbc/depot/expression/FunctionExp.java

@@ -20,16 +20,14 @@
 
 package com.samskivert.jdbc.depot.expression;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
+import com.samskivert.jdbc.depot.PersistentRecord;
 
 /**
  * An expression for a function, e.g. FLOOR(blah).
  */
-public class FunctionExp
-    implements SQLExpression
+public class FunctionExp implements SQLExpression
 {
     /**
      * Create a new FunctionExp with the given function and arguments.
@@ -41,27 +39,28 @@ public class FunctionExp
     }
 
     // from SQLExpression
-    public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+    public void accept (ExpressionVisitor builder)
+        throws Exception
     {
-        builder.append(_function);
-        builder.append("(");
-        for (int ii = 0; ii < _arguments.length; ii ++) {
-            if (ii > 0) {
-                builder.append(", ");
-            }
-            _arguments[ii].appendExpression(query, builder);
-        }
-        builder.append(")");
+        builder.visit(this);
     }
 
     // from SQLExpression
-    public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
         for (int ii = 0; ii < _arguments.length; ii ++) {
-            argIdx = _arguments[ii].bindExpressionArguments(pstmt, argIdx);
+            _arguments[ii].addClasses(classSet);
         }
-        return argIdx;
+    }
+
+    public String getFunction ()
+    {
+        return _function;
+    }
+
+    public SQLExpression[] getArguments ()
+    {
+        return _arguments;
     }
 
     /** The literal name of this function, e.g. FLOOR */

src/java/com/samskivert/jdbc/depot/expression/LiteralExp.java

@@ -20,10 +20,9 @@
 
 package com.samskivert.jdbc.depot.expression;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
+import com.samskivert.jdbc.depot.PersistentRecord;
 
 /**
  * An expression for things we don't support natively, e.g. COUNT(*).
@@ -38,16 +37,19 @@ public class LiteralExp
     }
 
     // from SQLExpression
-    public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+    public void accept (ExpressionVisitor builder) throws Exception
     {
-        builder.append(_text);
+        builder.visit(this);
     }
 
     // from SQLExpression
-    public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        return argIdx;
+    }
+
+    public String getText ()
+    {
+        return _text;
     }
 
     /** The literal text of this expression, e.g. COUNT(*) */

src/java/com/samskivert/jdbc/depot/expression/SQLExpression.java

@@ -20,10 +20,10 @@
 
 package com.samskivert.jdbc.depot.expression;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.SQLBuilder;
 
 /**
  * Represents an SQL expression, e.g. column name, function, or constant.
@@ -31,16 +31,19 @@ import com.samskivert.jdbc.depot.QueryBuilderContext;
 public interface SQLExpression
 {
     /**
-     * Construct the SQL form of this expression. The implementor is invited to call methods on the
-     * Query object to e.g. resolve the current table abbreviations associated with classes.
+     * Most uses of this class have been implemented with a visitor pattern. Create your own
+     * {@link ExpressionVisitor} and call this method with it.
+     * 
+     * @see SQLBuilder
      */
-    public void appendExpression (QueryBuilderContext<?> query, StringBuilder builder);
+    public void accept (ExpressionVisitor builder)
+        throws Exception;
 
     /**
-     * Bind any objects that were referenced in the generated SQL.  For each ? that appears in the
-     * SQL, precisely one parameter must be claimed and bound in this method, and argIdx
-     * incremented and returned.
+     * Adds all persistent classes that are brought into the SQL context by this clause: FROM
+     * clauses, JOINs, UPDATEs, anything that could create a new table abbreviation. This method
+     * should recurse into any subordinate state that may in turn bring in new classes so that
+     * sub-queries work correctly.
      */
-    public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException;
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet);
 }

src/java/com/samskivert/jdbc/depot/expression/ValueExp.java

@@ -20,10 +20,9 @@
 
 package com.samskivert.jdbc.depot.expression;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
+import com.samskivert.jdbc.depot.PersistentRecord;
 
 /**
  * A Java value that is bound as a parameter to the query, e.g. 1 or 'abc'.
@@ -31,25 +30,27 @@ import com.samskivert.jdbc.depot.QueryBuilderContext;
 public class ValueExp
     implements SQLExpression
 {
-    public ValueExp (Comparable _value)
+    public ValueExp (Object _value)
     {
         this._value = _value;
     }
 
     // from SQLExpression
-    public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+    public void accept (ExpressionVisitor builder) throws Exception
     {
-        builder.append("?");
+        builder.visit(this);
     }
 
     // from SQLExpression
-    public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-        throws SQLException
+    public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
     {
-        pstmt.setObject(argIdx ++, _value);
-        return argIdx;
+    }
+
+    public Object getValue ()
+    {
+        return _value;
     }
 
     /** The value to be bound to the SQL parameters. */
-    protected Comparable _value;
+    protected Object _value;
 }

src/java/com/samskivert/jdbc/depot/operator/Arithmetic.java

@@ -20,7 +20,6 @@
 
 package com.samskivert.jdbc.depot.operator;
 
-import com.samskivert.jdbc.depot.expression.ColumnExp;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 import com.samskivert.jdbc.depot.operator.SQLOperator.BinaryOperator;
 
@@ -34,11 +33,6 @@ public abstract class Arithmetic
     /** The SQL '+' operator. */
     public static class Add extends BinaryOperator
     {
-        public Add (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public Add (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -50,7 +44,7 @@ public abstract class Arithmetic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "+";
         }
@@ -59,11 +53,6 @@ public abstract class Arithmetic
     /** The SQL '-' operator. */
     public static class Sub extends BinaryOperator
     {
-        public Sub (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public Sub (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -75,7 +64,7 @@ public abstract class Arithmetic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "-";
         }
@@ -84,11 +73,6 @@ public abstract class Arithmetic
     /** The SQL '*' operator. */
     public static class Mul extends BinaryOperator
     {
-        public Mul (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public Mul (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -100,7 +84,7 @@ public abstract class Arithmetic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "*";
         }
@@ -109,11 +93,6 @@ public abstract class Arithmetic
     /** The SQL '/' operator. */
     public static class Div extends BinaryOperator
     {
-        public Div (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public Div (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -125,7 +104,7 @@ public abstract class Arithmetic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "/";
         }
@@ -134,11 +113,6 @@ public abstract class Arithmetic
     /** The SQL '&' operator. */
     public static class BitAnd extends BinaryOperator
     {
-        public BitAnd (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public BitAnd (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -150,7 +124,7 @@ public abstract class Arithmetic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "&";
         }
@@ -159,11 +133,6 @@ public abstract class Arithmetic
     /** The SQL '|' operator. */
     public static class BitOr extends BinaryOperator
     {
-        public BitOr (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public BitOr (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -175,7 +144,7 @@ public abstract class Arithmetic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "|";
         }

src/java/com/samskivert/jdbc/depot/operator/Conditionals.java

@@ -20,15 +20,12 @@
 
 package com.samskivert.jdbc.depot.operator;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
 import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
 import com.samskivert.jdbc.depot.PersistentRecord;
 import com.samskivert.jdbc.depot.expression.ColumnExp;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
-import com.samskivert.jdbc.depot.operator.SQLOperator.BinaryOperator;
 
 /**
  * A convenient container for implementations of conditional operators.  Classes that value brevity
@@ -56,31 +53,28 @@ public abstract class Conditionals
             _column = column;
         }
 
-        // from SQLExpression
-        public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+        public ColumnExp getColumn()
         {
-            _column.appendExpression(query, builder);
-            builder.append(" is null");
+            return _column;
         }
 
         // from SQLExpression
-        public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-            throws SQLException
+        public void accept (ExpressionVisitor builder) throws Exception
+        {
+            builder.visit(this);
+        }
+
+        // from SQLExpression
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
         {
-            return argIdx;
         }
 
         protected ColumnExp _column;
     }
 
     /** The SQL '=' operator. */
-    public static class Equals extends BinaryOperator
+    public static class Equals extends SQLOperator.BinaryOperator
     {
-        public Equals (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public Equals (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -92,20 +86,15 @@ public abstract class Conditionals
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "=";
         }
     }
 
     /** The SQL '<' operator. */
-    public static class LessThan extends BinaryOperator
+    public static class LessThan extends SQLOperator.BinaryOperator
     {
-        public LessThan (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public LessThan (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -117,20 +106,15 @@ public abstract class Conditionals
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "<";
         }
     }
 
     /** The SQL '<=' operator. */
-    public static class LessThanEquals extends BinaryOperator
+    public static class LessThanEquals extends SQLOperator.BinaryOperator
     {
-        public LessThanEquals (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public LessThanEquals (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -142,20 +126,15 @@ public abstract class Conditionals
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "<=";
         }
     }
 
     /** The SQL '>' operator. */
-    public static class GreaterThan extends BinaryOperator
+    public static class GreaterThan extends SQLOperator.BinaryOperator
     {
-        public GreaterThan (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public GreaterThan (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -167,20 +146,15 @@ public abstract class Conditionals
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return ">";
         }
     }
 
     /** The SQL '>=' operator. */
-    public static class GreaterThanEquals extends BinaryOperator
+    public static class GreaterThanEquals extends SQLOperator.BinaryOperator
     {
-        public GreaterThanEquals (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public GreaterThanEquals (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -192,7 +166,7 @@ public abstract class Conditionals
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return ">=";
         }
@@ -202,16 +176,6 @@ public abstract class Conditionals
     public static class In
         implements SQLOperator
     {
-        public In (String pColumn, Comparable... values)
-        {
-            this(new ColumnExp(null, pColumn), values);
-        }
-
-        public In (String pColumn, Collection<? extends Comparable> values)
-        {
-            this(new ColumnExp(null, pColumn), values.toArray(new Comparable[values.size()]));
-        }
-
         public In (Class<? extends PersistentRecord> pClass, String pColumn, Comparable... values)
         {
             this(new ColumnExp(pClass, pColumn), values);
@@ -232,107 +196,40 @@ public abstract class Conditionals
             _values = values;
         }
 
-        // from SQLExpression
-        public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+        public In (ColumnExp pColumn, Collection<? extends Comparable> values)
         {
-            _column.appendExpression(query, builder);
-            builder.append(" in (");
-            for (int ii = 0; ii < _values.length; ii ++) {
-                if (ii > 0) {
-                    builder.append(", ");
+            this(pColumn, values.toArray(new Comparable[values.size()]));
         }
-                builder.append("?");
+
+        public ColumnExp getColumn ()
+        {
+            return _column;
         }
-            builder.append(")");
+
+        public Comparable[] getValues ()
+        {
+            return _values;
         }
 
         // from SQLExpression
-        public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-            throws SQLException
+        public void accept (ExpressionVisitor builder) throws Exception
         {
-            for (int ii = 0; ii < _values.length; ii++) {
-                pstmt.setObject(argIdx ++, _values[ii]);
+            builder.visit(this);
         }
-            return argIdx;
+
+        // from SQLExpression
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+        {
+            _column.addClasses(classSet);
         }
 
         protected ColumnExp _column;
         protected Comparable[] _values;
     }
 
-    /** The MySQL 'match (...) against (...)' operator. */
-    public static class Match
-        implements SQLOperator
-    {
-        public enum Mode { DEFAULT, BOOLEAN, NATURAL_LANGUAGE };
-
-        public Match (String query, Mode mode, boolean queryExpansion, String... pColumns)
-        {
-            _query = query;
-            _mode = mode;
-            _queryExpansion = queryExpansion;
-            _columns = new ColumnExp[pColumns.length];
-            for (int ii = 0; ii < pColumns.length; ii++) {
-                _columns[ii] = new ColumnExp(null, pColumns[ii]);
-            }
-        }
-
-        public Match (String query, Mode mode, boolean queryExpansion, ColumnExp... columns)
-        {
-            _query = query;
-            _queryExpansion = queryExpansion;
-            _mode = mode;
-            _columns = columns;
-        }
-
-        // from SQLExpression
-        public void appendExpression (QueryBuilderContext query, StringBuilder builder)
-        {
-            builder.append("match(");
-            int idx = 0;
-            for (ColumnExp column : _columns) {
-                if (idx++ > 0) {
-                    builder.append(", ");
-                }
-                column.appendExpression(query, builder);
-            }
-            builder.append(") against (?");
-            switch (_mode) {
-            case BOOLEAN:
-                builder.append(" in boolean mode");
-                break;
-            case NATURAL_LANGUAGE:
-                builder.append(" in natural language mode");
-                break;
-            }
-            if (_queryExpansion) {
-                builder.append(" with query expansion");
-            }
-            builder.append(")");
-        }
-
-        // from SQLExpression
-        public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-            throws SQLException
-        {
-            pstmt.setString(argIdx++, _query);
-            return argIdx;
-        }
-
-        protected String _query;
-        protected Mode _mode;
-        protected boolean _queryExpansion;
-        protected ColumnExp[] _columns;
-    }
-
     /** The SQL ' like ' operator. */
-    public static class Like extends BinaryOperator
+    public static class Like extends SQLOperator.BinaryOperator
     {
-        public Like (String pColumn, Comparable value)
-        {
-            super(new ColumnExp(pColumn), value);
-        }
-
         public Like (SQLExpression column, Comparable value)
         {
             super(column, value);
@@ -344,9 +241,64 @@ public abstract class Conditionals
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return " like ";
         }
     }
+
+    /** The MySQL 'match (...) against (...)' operator. */
+    @Deprecated
+    public static class Match
+        implements SQLOperator
+    {
+        public enum Mode { DEFAULT, BOOLEAN, NATURAL_LANGUAGE };
+
+        public Match (String query, Mode mode, boolean queryExpansion, ColumnExp... columns)
+        {
+            _query = query;
+            _queryExpansion = queryExpansion;
+            _mode = mode;
+            _columns = columns;
+        }
+
+        public String getQuery ()
+        {
+            return _query;
+        }
+
+        public Mode getMode ()
+        {
+            return _mode;
+        }
+
+        public boolean isQueryExpansion ()
+        {
+            return _queryExpansion;
+        }
+
+        public ColumnExp[] getColumns ()
+        {
+            return _columns;
+        }
+
+        // from SQLExpression
+        public void accept (ExpressionVisitor builder) throws Exception
+        {
+            builder.visit(this);
+        }
+
+        // from SQLExpression
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+        {
+            for (ColumnExp column : _columns) {
+                column.addClasses(classSet);
+            }
+        }
+
+        protected String _query;
+        protected Mode _mode;
+        protected boolean _queryExpansion;
+        protected ColumnExp[] _columns;
+    }
 }

src/java/com/samskivert/jdbc/depot/operator/Logic.java

@@ -20,12 +20,11 @@
 
 package com.samskivert.jdbc.depot.operator;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
-import com.samskivert.jdbc.depot.operator.SQLOperator.MultiOperator;
 
 /**
  * A convenient container for implementations of logical operators.  Classes that value brevity
@@ -37,7 +36,7 @@ public abstract class Logic
     /**
      * Represents a condition that is false iff all its subconditions are false.
      */
-    public static class Or extends MultiOperator
+    public static class Or extends SQLOperator.MultiOperator
     {
         public Or (SQLExpression... conditions)
         {
@@ -45,7 +44,7 @@ public abstract class Logic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "or";
         }
@@ -54,7 +53,7 @@ public abstract class Logic
     /**
      * Represents a condition that is true iff all its subconditions are true.
      */
-    public static class And extends MultiOperator
+    public static class And extends SQLOperator.MultiOperator
     {
         public And (SQLExpression... conditions)
         {
@@ -62,7 +61,7 @@ public abstract class Logic
         }
 
         @Override
-        protected String operator()
+        public String operator()
         {
             return "and";
         }
@@ -76,23 +75,24 @@ public abstract class Logic
     {
         public Not (SQLExpression condition)
         {
-            super();
             _condition = condition;
         }
         
-        // from SQLExpression
-        public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+        public SQLExpression getCondition ()
         {
-            builder.append(" not (");
-            _condition.appendExpression(query, builder);
-            builder.append(")");
+            return _condition;
         }
 
         // from SQLExpression
-        public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-            throws SQLException
+        public void accept (ExpressionVisitor builder) throws Exception
         {
-            return _condition.bindExpressionArguments(pstmt, argIdx);
+            builder.visit(this);
+        }
+
+        // from SQLExpression
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
+        {
+            _condition.addClasses(classSet);
         }
         
         protected SQLExpression _condition;

src/java/com/samskivert/jdbc/depot/operator/SQLOperator.java

@@ -20,10 +20,10 @@
 
 package com.samskivert.jdbc.depot.operator;
 
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
+import java.util.Collection;
 
-import com.samskivert.jdbc.depot.QueryBuilderContext;
+import com.samskivert.jdbc.depot.PersistentRecord;
+import com.samskivert.jdbc.depot.expression.ExpressionVisitor;
 import com.samskivert.jdbc.depot.expression.SQLExpression;
 import com.samskivert.jdbc.depot.expression.ValueExp;
 
@@ -42,37 +42,32 @@ public interface SQLOperator extends SQLExpression
     {
         public MultiOperator (SQLExpression ... conditions)
         {
-            super();
             _conditions = conditions;
         }
 
         // from SQLExpression
-        public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+        public void accept (ExpressionVisitor builder) throws Exception
         {
-            for (int ii = 0; ii < _conditions.length; ii++) {
-                if (ii > 0) {
-                    builder.append(" ").append(operator()).append(" ");
-                }
-                builder.append("(");
-                _conditions[ii].appendExpression(query, builder);
-                builder.append(")");
-            }
+            builder.visit(this);
         }
         
         // from SQLExpression
-        public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-            throws SQLException
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
         {
-            for (int ii = 0; ii < _conditions.length; ii++) {
-                argIdx = _conditions[ii].bindExpressionArguments(pstmt, argIdx);
+            for (int ii = 0; ii < _conditions.length; ii ++) {
+                _conditions[ii].addClasses(classSet);
             }
-            return argIdx;
+        }
+
+        public SQLExpression[] getConditions ()
+        {
+            return _conditions;
         }
 
         /**
          * Returns the text infix to be used to join expressions together.
          */
-        protected abstract String operator ();
+        public abstract String operator ();
 
         protected SQLExpression[] _conditions;
     }
@@ -94,26 +89,32 @@ public interface SQLOperator extends SQLExpression
         }
 
         // from SQLExpression
-        public void appendExpression (QueryBuilderContext query, StringBuilder builder)
+        public void accept (ExpressionVisitor builder) throws Exception
         {
-            _lhs.appendExpression(query, builder);
-            builder.append(operator());
-            _rhs.appendExpression(query, builder);
+            builder.visit(this);
         }
 
         // from SQLExpression
-        public int bindExpressionArguments (PreparedStatement pstmt, int argIdx)
-            throws SQLException
+        public void addClasses (Collection<Class<? extends PersistentRecord>> classSet)
         {
-            argIdx = _lhs.bindExpressionArguments(pstmt, argIdx);
-            argIdx = _rhs.bindExpressionArguments(pstmt, argIdx);
-            return argIdx;
+            _lhs.addClasses(classSet);
+            _rhs.addClasses(classSet);
         }
         
         /**
          * Returns the string representation of the operator.
          */
-        protected abstract String operator();
+        public abstract String operator();
+
+        public SQLExpression getLeftHandSide ()
+        {
+            return _lhs;
+        }
+
+        public SQLExpression getRightHandSide ()
+        {
+            return _rhs;
+        }
 
         protected SQLExpression _lhs;
         protected SQLExpression _rhs;