diff --git a/plugins/UserFlag/User_flag_profile.php b/plugins/UserFlag/User_flag_profile.php
index 6582594524..6bf47071b2 100644
--- a/plugins/UserFlag/User_flag_profile.php
+++ b/plugins/UserFlag/User_flag_profile.php
@@ -89,6 +89,17 @@ class User_flag_profile extends Memcached_DataObject
         return array('profile_id' => 'N', 'user_id' => 'N');
     }
 
+    /**
+     * return key definitions for DB_DataObject
+     *
+     * @return array key definitions
+     */
+
+    function keyTypes()
+    {
+        return $this->keys();
+    }
+
     /**
      * Get a single object with multiple keys
      *