From bfc55f66eb1e898aa282162102fad481a06f9bfc Mon Sep 17 00:00:00 2001
From: mdb <mdb@6335cc39-0255-0410-8fd6-9bcaacd3b74c>
Date: Fri, 9 Feb 2007 20:41:30 +0000
Subject: [PATCH] Make our Rename migration more lenient about having already
 been performed.

git-svn-id: https://samskivert.googlecode.com/svn/trunk@2046 6335cc39-0255-0410-8fd6-9bcaacd3b74c
---
 .../jdbc/depot/EntityMigration.java           | 28 ++++++++++++++++---
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/java/com/samskivert/jdbc/depot/EntityMigration.java b/src/java/com/samskivert/jdbc/depot/EntityMigration.java
index 9d21c1ee..6f394261 100644
--- a/src/java/com/samskivert/jdbc/depot/EntityMigration.java
+++ b/src/java/com/samskivert/jdbc/depot/EntityMigration.java
@@ -3,7 +3,7 @@
 //
 // 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
@@ -25,6 +25,8 @@ import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.HashMap;
 
+import com.samskivert.jdbc.JDBCUtil;
+
 import static com.samskivert.jdbc.depot.Log.log;
 
 /**
@@ -75,9 +77,27 @@ public abstract class EntityMigration extends Modifier
             try {
                 log.info("Changing '" + _oldColumnName + "' to '" + _newColumnDef + "' in " +
                          _tableName);
-                return stmt.executeUpdate(
-                    "alter table " + _tableName + " change column " + _oldColumnName + " " +
-                    _newColumnDef);
+
+                if (!JDBCUtil.tableContainsColumn(conn, _tableName, _oldColumnName)) {
+                    if (JDBCUtil.tableContainsColumn(conn, _tableName, _newColumnName)) {
+                        // we'll accept this inconsistency
+                        log.warning("Column rename appears already performed.");
+                        return 0;
+                    }
+                    // but this is not OK
+                    throw new IllegalArgumentException(
+                        _tableName + " does not contain '" + _oldColumnName + "'");
+                }
+
+                // nor is this
+                if (JDBCUtil.tableContainsColumn(conn, _tableName, _newColumnName)) {
+                    throw new IllegalArgumentException(
+                        _tableName + " already contains '" + _newColumnName + "'");
+                }
+
+                return stmt.executeUpdate("alter table " + _tableName + " change column " +
+                                          _oldColumnName + " " + _newColumnDef);
+
             } finally {
                 stmt.close();
             }