On Developer.com, Jason Gilmore has posted This new tutorial that steps you through the creation of an ajax-enabled shopping cart that combines PHP and Prototype.

In the latest installment of this ongoing PHP series, I'll show you how to build a shopping cart using PHP, session handling, and the Prototype JavaScript library (introduced in an earlier installment). The cart allows users to add and delete products from the cart, as well as change cart quantities. And of course, the interaction is seemingly instantaneous, allowing for the user to continue shopping without waiting for the page to reload.

He creates the database table first (bottom up approach), then moves to the PHP code to handle the request/responses for the shopping cart, and with a little bit of session magic to connect the cart to the user and the Prototype tossed in, the cart is complete.