PHP mysqli select_db() Function

Example - Object Oriented style

Change the default database for the connection:

<?php
$mysqli = new mysqli("localhost","my_user","my_password","my_db");

if ($mysqli -> connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
exit();
}

// Return name of current default database
if ($result = $mysqli -> query("SELECT DATABASE()")) {
$row = $result -> fetch_row();
echo "Default database is " . $row[0];
$result -> close();
}

// Change db to "test" db
$mysqli -> select_db("test");

// Return name of current default database
if ($result = $mysqli -> query("SELECT DATABASE()")) {
$row = $result -> fetch_row();
echo "Default database is " . $row[0];
$result -> close();
}

$mysqli -> close();
?>

Look at example of procedural style at the bottom.

Definition and Usage

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

Syntax

Object oriented style:

$mysqli -> select_db(name)

Procedural style:

mysqli_select_db(connection, name)

Parameter Values

Parameter	Description
connection	Required. Specifies the MySQL connection to use
name	Required. Specifies the database name

Technical Details

Return Value:	TRUE on success. FALSE on failure
PHP Version:	5+

Example - Procedural style

Change the default database for the connection:

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");

if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit;
}

// Return name of current default database
if ($result = mysqli_query($con, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
echo "Default database is " . $row[0];
mysqli_free_result($result);
}

// Change db to "test" db
mysqli_select_db($con, "test");

// Return name of current default database
if ($result = mysqli_query($con, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
echo "Default database is " . $row[0];
mysqli_free_result($result);
}

// Close connection
mysqli_close($con);
?>

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