MySQL and PHP
Copyright 1997-2021 the PHP Documentation Group.
mysqli::change_user
mysqli_change_user
Changes the user of the specified database connection
Object oriented style
public bool mysqli::change_user(string user,
string password,
string database);
Procedural style
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.
link
Procedural style only: A link identifier returned by
mysqli_connect
or
mysqli_init
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.
Returns true
on success or
false
on failure.
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.
Example 3.33 mysqli::change_user
example
Object oriented style
<?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(); ?>
Procedural style
<?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); ?>
The above examples will output:
Default database: world Value of variable a is NULL
mysqli_connect
|
mysqli_select_db
|