The one-to-many relationship is by far the most common and most important relationship type. Almost any relational database offers numerous examples of one-to-many relationships. In this section, I provide two examples of one-to-many relationships using the order-entry model, and two using the Classic TV database you worked with in Chapter 2. This way, you'll have plenty of opportunity to see one-to-many relationships at work.
An Order-Entry Model
Let's start with two examples from a typical order-entry model, such as the Northwind sample database. As a wholesaler of camping equipment, you have a table for customer contact information (Table 3.1); it has data about the subject customers. You also have a table for orders ...