From da176436242634acefa16f18d246302f54d9160c Mon Sep 17 00:00:00 2001
From: Pinaki Poddar <ppoddar@apache.org>
Date: Fri, 8 May 2009 01:31:37 +0000
Subject: [PATCH] OPENJA-1070:support for composite foreign keys on MySQL
 Version >= 5

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@772828 13f79535-47bb-0310-9956-ffa450edef68
---
 .../java/org/apache/openjpa/jdbc/sql/DBDictionary.java    | 3 +++
 .../java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java | 8 +-------
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java
index 628f2c840..2383c2f3b 100644
--- a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java
+++ b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/DBDictionary.java
@@ -181,6 +181,7 @@ public class DBDictionary
     public int maxIndexNameLength = 128;
     public int maxIndexesPerTable = Integer.MAX_VALUE;
     public boolean supportsForeignKeys = true;
+    public boolean supportsForeignKeysComposite = true;
     public boolean supportsUniqueConstraints = true;
     public boolean supportsDeferredConstraints = true;
     public boolean supportsRestrictDeleteAction = true;
@@ -3381,6 +3382,8 @@ public class DBDictionary
     protected String getForeignKeyConstraintSQL(ForeignKey fk) {
         if (!supportsForeignKeys)
             return null;
+        if (fk.getColumns().length > 0 && !supportsForeignKeysComposite)
+            return null;
         if (fk.getDeleteAction() == ForeignKey.ACTION_NONE)
             return null;
         if (fk.isDeferred() && !supportsDeferredForeignKeyConstraints())
diff --git a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
index 5ff0aa6d9..a1752d55c 100644
--- a/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
+++ b/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
@@ -141,6 +141,7 @@ public class MySQLDictionary
         if (maj < 4 || (maj == 4 && min < 1)) {
             supportsSubselect = false;
             allowsAliasInBulkClause = false;
+            supportsForeignKeysComposite = false;
         }
         if (maj > 5 || (maj == 5 && min >= 1))
             supportsXMLColumn = true;
@@ -216,13 +217,6 @@ public class MySQLDictionary
         System.arraycopy(sql, 0, ret, cols.length, sql.length);
         return ret;
     }
-
-    protected String getForeignKeyConstraintSQL(ForeignKey fk) {
-        // mysql does not support composite foreign keys
-        if (fk.getColumns().length > 1)
-            return null;
-        return super.getForeignKeyConstraintSQL(fk);
-    }
     
     public String[] getDeleteTableContentsSQL(Table[] tables) {
         // mysql >= 4 supports more-optimal delete syntax