Data Model Example

The following model of a database was constructed for a hypothetical video store and appears in the following figure:

The data model of the video store, along with definitions of the objects presented on it, makes the following assertions:

This is a relatively small model, but it says a lot about the video rental store. From it, you get an idea of what a database for the business should look like, and you get a good picture of the business. There are several different types of graphical objects in this diagram. The entities, attributes, and relationships, along with the other symbols, describe our business rules. In the following chapters, you will learn more about what the different graphical objects mean and how to use CA ERwin DM to create your own logical and physical data models.