Learning from the Data Model
In the previous chapter, we attempted to extract the essential tasks involved in a real-world problem and express them with use cases. We also made a first attempt at determining the data that are necessary to support those tasks and formed an initial data model, which we depicted with a class diagram. In this chapter, we look more closely at the data model to see how it can further our understanding of a database system.
A data model is a precise description of the data stored for a real–world problem, in much the same way that a mathematical equation describes a real-world physical event, or an architectural ...