Below is the ERD (Entity Relationship Diagram) for the bookstore database used in this series. I should have posted it before. It is based on the database used in the SQL Clearly Explained text by Jan Harrington. It is a simple, straightforward design. One thing to note is the one-to-many relationship from customer to orders and then one-to-many to order_lines. There is then a many-to-one from the order_lines to the books. In this case the order_lines table is serving as an intersection table between the orders and books. All this is a a very common pattern in relational databases. It is one the student will encounter frequently when working with databases. Our little sample database design could be easily converted to serve many other similar sales or order processing use cases.
The diagram is from the diagram facility in SQL Server Management Studio.
