mysqli::select_db

mysqli_select_db

(PHP 5, PHP 7, PHP 8)

mysqli::select_db -- mysqli_select_db — Selects the default database for database queries

Description

Object-oriented style

public mysqli::select_db(string $database): bool

Procedural style

mysqli_select_db(mysqli $mysql, string $database): bool

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().

Parameters

mysql: Procedural style only: A mysqli object returned by mysqli_connect() or mysqli_init()
database: The database name.

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 mysqli::select_db() example

Object-oriented style

<?php

mysqli_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

<?php

mysqli_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.

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User Contributed Notes 1 note

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lori at astoundingteam dot com ¶

1 year ago

Note that the order of arguments for `mysqli_select_db` is opposite what it is for the deprecated `mysql_select_db`.