protected function _newId( MW_DB_Connection_Interface $conn, $sql )
	{
		$result = $conn->create( $sql )->execute();

		if( ( $row = $result->fetch( MW_DB_Result_Abstract::FETCH_NUM ) ) === false ) {
			throw new MShop_Exception( sprintf( 'ID of last inserted database record not available' ) );
		}
		$result->finish();

		return $row[0];
	}