PHP mysqli: select_db() function

Last update on August 19 2022 21:51:17 (UTC/GMT +8 hours)

mysqli_select_db() function/ mysqli::select_db

The mysqli_select_db() function/ mysqli::select_db is used to change the default database for the connection.

Syntax:

Object oriented style

bool mysqli::select_db ( string $dbname )

Procedural style

bool mysqli_select_db ( mysqli $link , string $dbname )

Parameter:

Name	Description		Required/Optional
link	A link identifier returned by mysqli_connect() or mysqli_init()		Required for procedural style only and Optional for Object oriented style
dbname	The database name.		Required

Usage: Procedural style

mysqli_select_db(connection,dbname);

Parameter:

Name	Description	Required/Optional
connection	Specifies the MySQL connection to use	Required
dbname	Specifies the default database to be used	Required

Return value:

Returns TRUE on success or FALSE on failure.

Version: PHP 5, PHP 7

Example of object oriented style:

<?php
$mysqli = new mysqli("localhost", "user1", "datasoft123", "hr");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* return name of current default database */
if ($result = $mysqli->query("SELECT DATABASE()")) {
    $row = $result->fetch_row();
    printf("Default database is %s.\n", $row[0]);
    $result->close();
}

/* change db to world db */
$mysqli->select_db("hr");

/* return name of current default database */
if ($result = $mysqli->query("SELECT DATABASE()")) {
    $row = $result->fetch_row();
    printf("Default database is %s.\n", $row[0]);
    $result->close();
}

$mysqli->close();
?>

Output:

Default database is hr. Default database is hr.

Example of the Procedural style

<?php
$link = mysqli_connect("localhost", "user1", "datasoft123", "hr");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* return name of current default database */
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
    $row = mysqli_fetch_row($result);
    printf("Default database is %s.\n", $row[0]);
    mysqli_free_result($result);
}

/* change db to world db */
mysqli_select_db($link, "hr");

/* return name of current default database */
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
    $row = mysqli_fetch_row($result);
    printf("Default database is %s.\n", $row[0]);
    mysqli_free_result($result);
}

mysqli_close($link);
?>

Output:

Default database is hr.
Default database is hr.

See also

PHP Function Reference

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