ABSTRACT
Throughout this book we developed the rules for mapping an ER diagram to a relational database. In this chapter we present a summary of the mapping rules, and then discuss reverseengineering.
We often find that databases exist without an accompanying ER diagram. The ER diagram is documentation; and just as computer programs require documentation, so do databases. Therefore, we have included a section on reverse-engineering ER diagrams; that is, working from a relational database back to an ER diagram. For reverse-engineering, we present a series of steps to develop a diagram from the data.
