How can PHP sessions be effectively used to track and manage user login information in a secure manner?

To effectively track and manage user login information in a secure manner using PHP sessions, you can store the user's unique identifier (such as their user ID) in the session after a successful login. This allows you to identify the user throughout their session without storing sensitive information in cookies or URLs.

// Start the session
session_start();

// Check if the user is logged in
if(isset($_SESSION['user_id'])) {
    // User is logged in, retrieve user information from database using $_SESSION['user_id']
    $user_id = $_SESSION['user_id'];
    // Query database for user information using $user_id
} else {
    // User is not logged in, redirect to login page
    header("Location: login.php");
    exit();
}