Create DB if not exists using mysqli + php

Question

I am trying to create a database using mysqli if the database name doesn't exist using the following code:

<?php

$link = mysqli_connect("localhost", "root", "", "php1") ; 
if(mysqli_connect_errno()){
    echo mysqli_connect_error();
    $query = "CREATE DATABASE php1";
    if(mysqli_query($link, $query)){
        echo "Success";
    } else {
        echo "Failure";
    }
}


?>
<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>        
        <a href="signup.php"><button type="button">Sign Up!</button></a>
        <a href="login.php"><button type="button">Log In</button></a>
    </body>
</html>

The code checks the db & it doesn't exists. Next I want to create the database if it does not exist but I am getting the following error always:

Warning: mysqli_connect(): (HY000/1049): Unknown database 'php1' in E:\xampp\htdocs\PhpProject1\index.php on line 3

Unknown database 'php1'

Warning: mysqli_query() expects parameter 1 to be mysqli, boolean given in E:\xampp\htdocs\PhpProject1\index.php on line 7

Failure

This way I can't get the new DB created. Does anybody has any idea how to correct this?

Nate · Accepted Answer · 2015-03-27 18:25:19Z

11

Three steps to fix this:

Don’t specify the database name when connecting.
Your SQL statement should be CREATE DATABASE IF NOT EXISTS php1.
Call mysqli_select_db($link, 'php1') to make that the default database for your connection.

edited Mar 27, 2015 at 18:25

answered Mar 27, 2015 at 18:19

Nate

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2 Comments

Amrit Over a year ago

Gee, Thanks! I was stuck here since a long time :) The first point was the most important one i think.

TamusJRoyce Over a year ago

$mysqli = new mysqli($DB_SERVER, $DB_USERNAME, $DB_PASSWORD, "", $DB_PORT); ... $mysqli->query('use ' . $DB_NAME . ';'); worked! Thank you!

Antoine Subit · Accepted Answer · 2022-03-10 13:20:41Z

1

// Enable error reporting for mysqli
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

// Connection to MySQL server without database name.
$connect = new mysqli('localhost', 'my_user', 'my_password');

// Set the desired charset after establishing a connection
$connect->set_charset('utf8mb4');

// Create database if not exists.
$databaseName = 'database_name';
$query = 'CREATE DATABASE IF NOT EXISTS ' . $databaseName;

// Use the new database for all future SQL queries.
mysqli_select_db($connect, $databaseName);

More information about mysqli_connect : https://www.php.net/manual/en/mysqli.construct.php

edited Mar 10, 2022 at 13:20

answered Mar 10, 2022 at 8:35

Antoine Subit

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1 Comment

Your Common Sense Over a year ago

Note it is not a good idea to make this code run constantly. It should be separate script that is run only once

Husam Ebish · Accepted Answer · 2022-05-23 16:03:05Z

-2

$connection = '';
$connection = new mysqli("db", "root", "example");
$query = mysqli_query($connection, "SHOW DATABASES LIKE 'company'");
$result = mysqli_num_rows($query);

if($result <=0){
$create = mysqli_query($connection, "CREATE DATABASE IF NOT EXISTS company;");
echo "Database created successifully";
}

answered May 23, 2022 at 16:03

Husam Ebish

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