This chapter first distinguishes two fundamental types of rules: operative rules and definitional rules (or structural rules). It then describes the various ways in which rules govern an organization:
1. some rules govern the business processes performed by organizations, their employees, customers, suppliers, and partners;
2. other rules govern user interfaces and electronic messages;
3. other rules ensure database integrity;
4. still other rules govern human behavior other than business processes.
Operative rules state what must or must not happen in particular circumstances, as in the following examples:
R15. Each flight booking request for a return journey must specify the return date.