Where do you want to store the product information? Are you talking about pre-purchase or post-purchase? The answer is probably in a mysql database or on the page in the add to cart server behavior depending on your catalog and how you want to manage the product information. 
I wanna know if there is an eCart function that can mess with the database table. Because if someone buys a product, I want the amount in stock to be subtracted by the amount that was bought. What is the easiest way to do this?


