php login session with database

if (!isset($_SESSION['loggedin'])) { header('Location: index. angkasa 17 login html'); exit; } $DATABASE_HOST = 'localhost'; $DATABASE_USER = 'root'; $DATABASE_PASS = ''; $DATABASE_NAME = 'phplogin'; $con = mysqli_connect($DATABASE_HOST, $DATABASE_USER, $DATABASE_PASS, $DATABASE_NAME); if (mysqli_connect_errno()) { exit('Failed to connect to MySQL: ' . bons login mysqli