diff --git a/UPGRADE.md b/UPGRADE.md
index ade59907b2a..9ccf8b68c20 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -1,5 +1,9 @@
 # Upgrade to 3.0
 
+## BC BREAK `DB2SchemaManager::_getPortableForeignKeyRuleDef()` removed
+
+The method was used internally and is no longer needed.
+
 ## BC BREAK `AbstractPlatform::get*Expression()` methods no loner accept integer values as arguments
 
 The following methods' arguments do not longer accept integer value:
diff --git a/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php b/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php
index 0b0bd96a1c9..32d8544fe90 100644
--- a/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php
+++ b/lib/Doctrine/DBAL/Schema/DB2SchemaManager.php
@@ -182,22 +182,6 @@ protected function _getPortableTableForeignKeysList($tableForeignKeys)
         return parent::_getPortableTableForeignKeysList($foreignKeys);
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    protected function _getPortableForeignKeyRuleDef($def)
-    {
-        if ($def === 'C') {
-            return 'CASCADE';
-        }
-
-        if ($def === 'N') {
-            return 'SET NULL';
-        }
-
-        return null;
-    }
-
     /**
      * {@inheritdoc}
      */