The starting point of our e-commerce application is the product catalog. In the real world, businesses may produce multiple catalogs for mutually exclusive or overlapping subsets of their products. Some examples are: fall and spring catalogs, catalogs based on a genre or sub-category of product such as catalogs for differing kinds of music (for example, rock versus classical), and many other possibilities. In some cases a single catalog may suffice, but allowing for multiple catalogs is a simple enhancement that will add flexibility and robustness to our application.
As an example, we will imagine a fictitious food and beverage company, CranStore.com, that specializes in cranberry products: cranberry drinks, food, and deserts. In addition, to promote tourism at their cranberry bog, they sell numerous gift items, including t-shirts, hats, mouse pads, and the like. We will consider this business to illustrate examples as they relate to the online store we are building...