Driver_Database_Driver_MySQL::set_charset

public function set_charset($charset)
{
    if (!$charset)return;

    $connection_id = $this->connection_id();
    $connection = Database_Driver_MySQL::$_connection_instance[$connection_id];

    if (!$connection_id || !$connection)
    {
        $this->connect();
        $this->set_charset($charset);
        return;
    }

    static $_set_names = null;
    if (null === $_set_names)
    {
        // Determine if we can use mysql_set_charset(), which is only
        // available on PHP 5.2.3+ when compiled against MySQL 5.0+
        $_set_names = ! function_exists('mysql_set_charset');
    }

    if (isset(Database_Driver_MySQL::$_current_charset[$connection_id]) && $charset==Database_Driver_MySQL::$_current_charset[$connection_id])
    {
        return true;
    }

    if (true===$_set_names)
    {
        // PHP is compiled against MySQL 4.x
        $status = (bool)mysql_query('SET NAMES ' . $this->quote($charset), $connection);
    }
    else
    {
        // PHP is compiled against MySQL 5.x
        $status = mysql_set_charset($charset, $connection);
    }

    if ($status === false)
    {
        throw new Exception('Error:' . mysql_error($connection), mysql_errno($connection));
    }

    # 记录当前设置的编码
    Database_Driver_MySQL::$_current_charset[$connection_id] = $charset;
}