mysqli::select_db

(PHP 5, PHP 7)

Selects the default database for database queries

bool mysqli::select_db ( string $dbname )

Object oriented style

Procedural style

bool mysqli_select_db ( mysqli $link , string $dbname )

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:

link

Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()

dbname

The database name.

Returns:

Returns TRUE on success or FALSE on failure.

Examples:

mysqli::select_db() example

Object oriented style

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

/* 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("world");

/* 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();
?>

Procedural style

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "test");

/* 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, "world");

/* 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);
?>

The above examples will output:

Default database is test.
Default database is world.