Why Does My PHP Code Fail to Connect to a MySQL Database?

Troubleshooting Connection Issues to a MySQL Database in PHP Using Mysqli Extension

Connecting to a MySQL database using the mysqli extension can be challenging, especially for beginners. This article addresses a common error encountered when attempting to connect to a server database.

The question presented a code snippet that failed to establish a connection to a remote database. The error message, "Failed to connect to MySQL," indicated a problem with the connection parameters. Upon investigating the code, we realized that the server name parameter was missing.

Solution 1: Specifying the Server Name

In PHP, the mysqli_connect function requires the server name as the first parameter. This parameter cannot be empty, so you should always provide a server name. For a remote database, use the server's IP address or domain name. For a local database, use "localhost".

$con = mysqli_connect("localhost", "username", "password", "databasename");

Solution 2: Using Mysqli Procedural

Alternatively, you can use the mysqli procedural style to establish the connection:

$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$con = mysqli_connect($servername, $username, $password);

// Check connection
if (!$con) {
    die("Connection failed: " . mysqli_connect_error());
}

Additional Notes for Local Development

For local development environments, you may need to adjust the server name and credentials:

$servername = "localhost";
$username = "root";
$password = "";

Where "root" is the default username for MySQL and "" (an empty string) is the password in most local setups.

By applying these solutions, you should be able to successfully connect to your MySQL database using the mysqli extension.

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