Chapter 13. The Database Schema

In the last chapter, we examined the conceptual data model, which defines the logical structure of the data. In this chapter, we turn to the database schema, which describes the physical structure of the data. Remember that the database schema is still a logical construct. In building it, you will describe the physical structure of the data in fairly abstract terms, albeit ones that correspond to the physical representation of the data. The actual physical representation is the responsibility of the database engine and need not concern you.