mysqli::change_user()

(PHP 5, PHP 7)

Changes the user of the specified database connection

说明

面向对象风格
mysqli::change_user(string $user,string $password,string $database): bool

过程化风格
mysqli_change_user(mysqli$link,string $user,string $password,string $database): bool

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

In order to successfully change users a valid$usernameand$passwordparameters 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
/* connect database test */
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");
/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
/* Set Variable a */
$mysqli->query("SET @a:=1");
/* reset all and select a new database */
$mysqli->change_user("my_user", "my_password", "world");
if ($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();
}
/* close connection */
$mysqli->close();
?>

过程化风格

<?php
/* connect database test */
$link = mysqli_connect("localhost", "my_user", "my_password", "test");
/* check connection */
if (!$link) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
/* Set Variable a */
mysqli_query($link, "SET @a:=1");
/* reset all and select a new database */
mysqli_change_user($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);
}
/* close connection */
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