Chapter 2 Data Models Discussion Focus Although all of the topics covered in this chapter are important, our students have given us consistent feedback: If you can write precise business rules from a description of operations, database design is not that difficult. Perhaps it is useful to argue that the answers to questions 2 and 3 in the Review Questions section are the key to successful design. What are business rules, what is their source, and why are they crucial. Business rules are precisely written and unambiguous statements that are derived from a detailed description of an organization's operations. And, because the business rules are derived from a precise description of operations, much of the design's success depends on the accuracy of the description of operations.