What are the differences between using $_GET, $_POST, and $_REQUEST in PHP for handling form data and database interactions?

When handling form data and database interactions in PHP, it is important to choose the appropriate superglobal variable to use. $_GET is used to collect data sent in the URL, $_POST is used to collect data sent in the HTTP request body, and $_REQUEST can collect data from both GET and POST requests. It is recommended to use $_POST for sensitive data like passwords and $_GET for non-sensitive data to avoid security vulnerabilities.

// Example of using $_POST to handle form data and database interactions
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $username = $_POST["username"];
    $password = $_POST["password"];

    // Perform database interactions using $username and $password
}