mysqli
PHP Manual

mysqli::change_user

mysqli_change_user

Changes the user of the database connection

Description

Object-oriented style

public bool mysqli::change_user(string $username, #[\SensitiveParameter]string $password, stringnull $database)

Procedural style

bool mysqli_change_user(
    mysqli $mysql,
    string $username,
    #[\SensitiveParameter]string $password,
    stringnull $database
)

Attempts to connect to the specified database using the provided credentials.

In comparison to mysqli::connect, this method will not disconnect the current connection if the new connection cannot be opened.

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.

Parameters

mysql

Procedural style only: A mysqli object returned by mysqli_connect or mysqli_init

username

The MySQL user name.

password

The MySQL password.

database

The database name. If null or an empty string is passed, the connection to the server will be opened with no default database.

Return Values

Returns true on success or false on failure.

Errors/Exceptions

If mysqli error reporting is enabled (MYSQLI_REPORT_ERROR) and the requested operation fails, a warning is generated. If, in addition, the mode is set to MYSQLI_REPORT_STRICT, a mysqli_sql_exception is thrown instead.

Examples

Example #1 Resetting the connection session

Object-oriented style

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");

$mysqli->query("SET @a:=1");

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

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

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

Procedural style

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$link = mysqli_connect("localhost", "my_user", "my_password", "test");

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

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

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

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

The above examples will output:

Default database: world
Value of variable a is NULL

Example #2 If database is null the connection is opened without selecting any default database

Object-oriented style

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "test");

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

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

The above examples will output:

Default database:

Notes

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.

See Also

  • mysqli_connect
  • mysqli_select_db