Integrity Rules and Constraints

Read this chapter and pay attention to the section on business rules and how they are obtained from users. Take note of the business rule examples and answer the exercises at the end of the chapter.

Enterprise Constraints

Enterprise constraints – sometimes referred to as semantic constraints – are additional rules specified by users or database administrators and can be based on multiple tables.

Here are some examples.

  • A class can have a maximum of 30 students.
  • A teacher can teach a maximum of four classes per semester.
  • An employee cannot take part in more than five projects.
  • The salary of an employee cannot exceed the salary of the employee's manager.