mysqli::change_user

mysqli_change_user

(PHP 5)

mysqli::change_user -- mysqli_change_user — Changes the user of the specified database connection

说明

面向对象风格

bool mysqli::change_user ( string $user , string $password , string $database )

过程化风格

bool mysqli_change_user ( mysqli $link , string $user , string $password , string $database )

Changes the user of the specified database connection and sets the current database.

In order to successfully change users a valid username and password parameters must be provided and that user must have sufficient permissions to access the desired database. If for any reason authorization fails, the current user authentication will remain.

参数

link

仅以过程化样式：由 mysqli_connect() 或 mysqli_init() 返回的链接标识。

user

The MySQL user name.

password

The MySQL password.

database

The database to change to.

If desired, the NULL value may be passed resulting in only changing the user and not selecting a database. To select a database in this case use the mysqli_select_db() function.

返回值

成功时返回 TRUE ，或者在失败时返回 FALSE 。

注释

Note:

Using this command will always cause the current database connection to behave as if was a completely new database connection, regardless of if the operation was completed successfully. This reset includes performing a rollback on any active transactions, closing all temporary tables, and unlocking all locked tables.

范例

Example #1 mysqli::change_user() example

面向对象风格

  <?php

 
 $mysqli  = new  mysqli ( "localhost" ,  "my_user" ,  "my_password" ,  "test" );

 
 if ( mysqli_connect_errno ()) {
     printf ( "Connect failed: %s\n" ,  mysqli_connect_error ());
    exit();
}

 
 $mysqli -> query ( "SET @a:=1" );

 
 $mysqli -> change_user ( "my_user" ,  "my_password" ,  "world" );

if ( $result  =  $mysqli -> query ( "SELECT DATABASE()" )) {
     $row  =  $result -> fetch_row ();
     printf ( "Default database: %s\n" ,  $row [ 0 ]);
     $result -> close ();
}

if ( $result  =  $mysqli -> query ( "SELECT @a" )) {
     $row  =  $result -> fetch_row ();
    if ( $row [ 0 ] ===  NULL ) {
         printf ( "Value of variable a is NULL\n" );
    }
     $result -> close ();
}

 
 $mysqli -> close ();
 ?>

过程化风格

  <?php
 
 $link  =  mysqli_connect ( "localhost" ,  "my_user" ,  "my_password" ,  "test" );

 
 if (! $link ) {
     printf ( "Connect failed: %s\n" ,  mysqli_connect_error ());
    exit();
}

 
 mysqli_query ( $link ,  "SET @a:=1" );

 
 mysqli_change_user ( $link ,  "my_user" ,  "my_password" ,  "world" );

if ( $result  =  mysqli_query ( $link ,  "SELECT DATABASE()" )) {
     $row  =  mysqli_fetch_row ( $result );
     printf ( "Default database: %s\n" ,  $row [ 0 ]);
     mysqli_free_result ( $result );
}

if ( $result  =  mysqli_query ( $link ,  "SELECT @a" )) {
     $row  =  mysqli_fetch_row ( $result );
    if ( $row [ 0 ] ===  NULL ) {
         printf ( "Value of variable a is NULL\n" );
    }
     mysqli_free_result ( $result );
}

 
 mysqli_close ( $link );
 ?>

以上例程会输出：

Default database: world
Value of variable a is NULL

参见

mysqli_connect() - 别名 mysqli::__construct
mysqli_select_db() - 选择用于数据库查询的默认数据库