title: How to maintain multiple unique data for a single user for N number of users in a database
body: <p>I have to develop a shopping site where I need to maintain data like "Add to Cart" and "Previous Orders" for a single user, for N number of users in a database. E.g. if there is a user named "Mark" and I need to store his 5 items previously added to cart and 4 items as previous order and there are say 100 users like him whose data I need to store, How should I solve this problem? I am using PHP and MySQL.</p>