Data Rules and Integrity
Simple business rules
- Limits on data ranges
- Price > 0
- Salary < 100,000
- DateHired > 1/12/1995
- Choosing from a set
- Gender = M, F, Unknown
- Jurisdiction=City, County, State, Federal
Referential Integrity
- Foreign key values in one table must exist in the master table.
- Order(O#, Odate, C#,…)
- C# must exist in the customer table.