(PHP 5, PHP 7, PHP 8)
mysqli::select_db -- mysqli_select_db — Selects the default database for database queries
Object-oriented style
$database
): boolProcedural style
Selects the default database to be used when performing queries against the database connection.
Note:
This function should only be used to change the default database for the connection. You can select the default database with 4th parameter in mysqli_connect().
mysql
Procedural style only: A mysqli object returned by mysqli_connect() or mysqli_init()
database
The database name.
Returns true
on success or false
on failure.
If mysqli error reporting is enabled (MYSQLI_REPORT_ERROR
) and the requested operation fails,
a warning is generated. If, in addition, the mode is set to MYSQLI_REPORT_STRICT
,
a mysqli_sql_exception is thrown instead.
Example #1 mysqli::select_db() example
Object-oriented style
<?phpmysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);$mysqli = new mysqli("localhost", "my_user", "my_password", "test");/* get the name of the current default database */$result = $mysqli->query("SELECT DATABASE()");$row = $result->fetch_row();printf("Default database is %s.\n", $row[0]);/* change default database to "world" */$mysqli->select_db("world");/* get the name of the current default database */$result = $mysqli->query("SELECT DATABASE()");$row = $result->fetch_row();printf("Default database is %s.\n", $row[0]);
Procedural style
<?phpmysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);$link = mysqli_connect("localhost", "my_user", "my_password", "test");/* get the name of the current default database */$result = mysqli_query($link, "SELECT DATABASE()");$row = mysqli_fetch_row($result);printf("Default database is %s.\n", $row[0]);/* change default database to "world" */mysqli_select_db($link, "world");/* get the name of the current default database */$result = mysqli_query($link, "SELECT DATABASE()");$row = mysqli_fetch_row($result);printf("Default database is %s.\n", $row[0]);
The above examples will output:
Default database is test. Default database is world.