From a4dc9860de1a423f0c376a24e59164310dd2547e Mon Sep 17 00:00:00 2001
From: Par Winzell <zell@threerings.net>
Date: Wed, 8 Apr 2009 18:52:08 +0000
Subject: [PATCH] Fix index creation for MySQL.

---
 .../com/samskivert/depot/impl/BuildVisitor.java     | 13 ++++++++++---
 .../com/samskivert/depot/impl/MySQLBuilder.java     |  7 +++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/java/com/samskivert/depot/impl/BuildVisitor.java b/src/java/com/samskivert/depot/impl/BuildVisitor.java
index e6688a4..1a05696 100644
--- a/src/java/com/samskivert/depot/impl/BuildVisitor.java
+++ b/src/java/com/samskivert/depot/impl/BuildVisitor.java
@@ -545,9 +545,7 @@ public abstract class BuildVisitor implements ExpressionVisitor
             }
             comma = true;
 
-            _builder.append("(");
-            field.left.accept(this);
-            _builder.append(")");
+            appendIndexComponent(field.left);
             if (field.right == Order.DESC) {
                 // ascending is default, print nothing unless explicitly descending
                 _builder.append(" desc");
@@ -704,6 +702,15 @@ public abstract class BuildVisitor implements ExpressionVisitor
             "Persistent field has no definition [class=" + type + ", field=" + field + "]");
     }
 
+    // output one of potentially many fields in an index expression
+    protected void appendIndexComponent (SQLExpression expression)
+    {
+        // the standard builder wraps each field in its own parens
+        _builder.append("(");
+        expression.accept(this);
+        _builder.append(")");
+    }
+
     protected BuildVisitor (DepotTypes types)
     {
         _types = types;
diff --git a/src/java/com/samskivert/depot/impl/MySQLBuilder.java b/src/java/com/samskivert/depot/impl/MySQLBuilder.java
index 153a4c6..e9088af 100644
--- a/src/java/com/samskivert/depot/impl/MySQLBuilder.java
+++ b/src/java/com/samskivert/depot/impl/MySQLBuilder.java
@@ -140,6 +140,13 @@ public class MySQLBuilder
             _builder.append(field);
         }
 
+        @Override
+        protected void appendIndexComponent (SQLExpression expression)
+        {
+            // MySQL is never given complex expressions and hates parens, so just recurse
+            expression.accept(this);
+        }
+
         protected void renderMatch (FullText fullText)
         {
             _builder.append("match(");