Bidding sites are a popular way to buy and sell many products. In this post, we look at these online auctions from a buyer’s perspective. What does our data model need to handle the bidding process? There are many online auction sites (eBay, eBid, Webstore, Bonanza, etc.) where one can buy jewelry, clothing, electronics, and a lot more. How these sites work is simple: an item is listed, people bid on it, and the highest bidder wins the item, often at quite a discount.