(PHP 5, PHP 7, PHP 8)
mysqli::change_user -- mysqli_change_user — Changes the user of the database connection
Stile orientato agli oggetti
$username, #[\SensitiveParameter] string $password, ?string $database): boolStile procedurale
$mysql,$username,$password,$databaseAttempts 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.
linkSolo nello stile procedurale: un identificatore restituito da mysqli_connect() o mysqli_init()
usernameThe MySQL user name.
passwordThe 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.
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.
Example #1 Resetting the connection session
Stile orientato agli oggetti
<?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");
}Stile procedurale
<?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");
}I precedenti esempi visualizzeranno:
Default database: world Value of variable a is NULL
Example #2 If database is null the connection is opened without selecting any default database
Stile orientato agli oggetti
<?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]);I precedenti esempi visualizzeranno:
Default database:
Nota:
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.