# mysqlnd_uh_convert_to_mysqlnd

(PECL mysqlnd-uh >= 1.0.0-alpha)

mysqlnd_uh_convert_to_mysqlnd — Converts a MySQL connection handle into a mysqlnd connection handle

### 说明

mysqlnd_uh_convert_to_mysqlnd ( mysqli `&$mysql_connection` ) : resource

Converts a MySQL connection handle into a mysqlnd connection handle. After conversion you can execute mysqlnd library calls on the connection handle. This can be used to access mysqlnd functionality not made available through user space API calls.

The function can be disabled with mysqlnd_uh.enable. If mysqlnd_uh.enable is set to `FALSE` the function will not install the proxy and always return `TRUE`. Additionally, an error of the type E_WARNING may be emitted. The error message may read like PHP Warning: mysqlnd_uh_convert_to_mysqlnd(): (Mysqlnd User Handler) The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enable = false. You are not allowed to call this function [...].

### 参数

`MySQL connection handle`

  A MySQL connection handle of type mysql, mysqli or PDO_MySQL.

### 返回值

A mysqlnd connection handle.

### 更新日志

版本 | 说明
--- | ---
5.4.0 | The `mysql_connection` parameter can now be of type mysql, PDO_MySQL, or mysqli. Before, only the mysqli type was allowed.

### 范例

Example #1 mysqlnd_uh_convert_to_mysqlnd() example

    <?php
    /* PDO user API gives no access to connection thread id */
    $mysql_connection = new PDO("mysql:host=localhost;dbname=test", "root", "");

    /* Convert PDO MySQL handle to mysqlnd handle */
    $mysqlnd = mysqlnd_uh_convert_to_mysqlnd($mysql_connection);

    /* Create Proxy to call mysqlnd connection class methods */
    $obj = new MySQLndUHConnection();
    /* Call mysqlnd_conn::get_thread_id */
    var_dump($obj->getThreadId($mysqlnd));

    /* Use SQL to fetch connection thread id */
    var_dump($mysql_connection->query("SELECT CONNECTION_ID()")->fetchAll());
    ?>

以上例程会输出：

    int(27054)
    array(1) {
      [0]=>
      array(2) {
        ["CONNECTION_ID()"]=>
        string(5) "27054"
        [0]=>
        string(5) "27054"
      }
    }

### 参见

- mysqlnd_uh.enable