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mysqli::select_db

mysqli_select_db

(PHP 5, PHP 7)

mysqli::select_db -- mysqli_select_dbSelects 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.

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.

See Also

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User Contributed Notes 2 notes

up
-9
hwalker1 at btopenworld dot com
7 years ago
Note that in the second example, if the database "world" does not exist, the database selected does not change. You may need to add additional code to ensure that you are connected to the correct database.
up
-21
pjasiulewicz at gmail dot com
10 years ago
In some situations its useful to use this function for changing databases in general. We've tested it in production environment and it seams to be faster with switching databases than creating new connections.
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