CS 602 Server Side development hw5 please explain and comment the following php code

require_once('database.php');

// Get all courses $query = 'SELECT * FROM sk_courses ORDER BY courseID'; $statement = $db->prepare($query); $statement->execute(); $courses = $statement->fetchAll(); $statement->closeCursor(); ?>

part 2

$dsn = 'mysql:host=localhost;dbname=cs602db'; $username = 'cs602_user'; $password = 'cs602_secret';

try { $db = new PDO($dsn, $username, $password); } catch (PDOException $e) { $error_message = $e->getMessage(); include('database_error.php'); exit(); } ?>