The Ordering subsystem contains those classes and relationships that deal with the process of ordering merchandise from the bookstore.
The class diagram for this subsystem is shown in Figure B.2.
A customer is an individual or organization that has placed orders for books and other products offered by the store.
A customer must have purchased books; a user who simply browses to the site is not considered a customer until he or she places an order.
Customers remain active for six months after their last order. An active customer receives periodic e-mail reminders of sales ...