Modern web development has moved away from this pattern in favor of more secure and user-friendly methods:
try // Begin Transaction for data integrity $pdo->beginTransaction(); // The Query // This attempts to insert the row. // If the user_id + product_id combo already exists, it updates the quantity instead. $sql = "INSERT INTO cart_items (user_id, product_id, quantity) VALUES (:user_id, :product_id, 1) ON DUPLICATE KEY UPDATE quantity = quantity + 1"; add-cart.php num
This article dives deep into both the implementation and the security of the add-cart.php script, with a special focus on the num parameter. You will learn how to code a robust cart handler, avoid critical vulnerabilities, and follow best practices that keep your customers—and your business—safe. Modern web development has moved away from this
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A classic SQL injection vulnerability exists when the script directly concatenates user input into a database query without proper sanitisation. You will learn how to code a robust
The user ID returned was 000 . The System Administrator. But Elias was the only admin with clearance for that directory, and he hadn't touched the checkout code in months. Then, a new notification popped up on his screen. POST /checkout/add-cart.php?item_id=USER_ELIAS&num=0