SQL Server® 2008 Administration: Instant Reference

5.3. Implement Referential Integrity

Referential integrity enforces the relationship among entities in the database. Since you will store the data for an individual entity in a table, making sure that entities in one table are appropriately related to entities in another table is critical. For example, having an order in an Order table with no corresponding customer in a Customer table represents a referential integrity failure.

In a relational database environment, data is distributed across many tables. Each table represents a single entity in the real world. Real-world entities have relationships with each other, so it seems logical that entities in the database would also have relationships with each other. It is therefore critical that ...