7.3.8: Surrogate Key

When a key specified for an entity is meaningless to the entity and to end-users (it doesn’t describe any characteristic of an entity), the key is referred to as a surrogate key. A key that is not a surrogate key is often referred to as a natural key. Often a surrogate key is just a simple integer value assigned by the database system.

When database designs are implemented, surrogate keys can be useful to simplify references from one table to another (referential integrity) and the associated joins when tables are referenced in queries.