| Navigation: Glossary Index >====== database integrity ============ Under the relational model, database integrity consists of two general rules: ============ ============ 1. Each database file or table must have a primary key serving as a unique identifier for all records. ============ ============ 2. When a table has a foreign key matching the primary key of another table, each value in the foreign key must either equal a value in the primary key of the other table, or be null. ====== |    |