public static function createStatement( $sql, &$connection = null, $fetchMode = \PDO::FETCH_ASSOC )
    {
        $_db = self::_checkConnection( $connection );

        /** @var $_statement \PDOStatement */
        $_statement = $_db->prepare( $sql );

        if ( false !== $fetchMode )
        {
            $_statement->setFetchMode( $fetchMode );
        }

        return $_statement;
    }