public function getMetaData()
    {
        $metaData = parent::getMetaData();
        if ($metaData)
            return $metaData;
        $className = get_class($this);
        if (empty(self::$_md[$className])) { // override this from the parent to force it to get the new MetaData
            self::$_md[$className] = null;
            self::$_md[$className] = new CActiveRecordMetaData($this);
        }
        return self::$_md[$className];
    }