public function lockTables( $tables )
    {
        if ( is_array( $tables ) )
        {
            $tmp = '';

            foreach ( $tables as $table )
            {
                $tmp .= "$table, ";
            }

            $tmp = rtrim( $tmp, ', ' );

            $tables = $tmp;
        }

        $query = "LOCK TABLES $tables WRITE;";

        return $this->modify( $query );
    }