The heart of any online store is the selection of products offered to visiting customers. Yet, as simple as that may sound, creating online stores to present the vast array of products and product types has proven to be one of the most challenging quests for platform programmers.

If all stores sold each product as an individual item without different colors, sizes, or add-ons, e-commerce would be much simpler. But that's not how the real world works. If you sell t-shirts (the classic example for this discussion), you might sell each color as a separate item, especially if you only offer a few shirts. However, it would make shopping very cumbersome to your customers if you also had each size of each color listed as a separate product.

People shop by product style, then decide upon variations such as size and color. To reflect this shopping "workflow," we need to create products in our store that are presented in the most convenient and logical manner...