Martyn Rhisiart Jones, Madrid, 4th February 2026.

Introduction

In data modelling and database design, keys play a fundamental role in uniquely identifying records and defining relationships between tables. One of the most widely used types of keys, especially in analytical systems and data warehouses, is the surrogate key.

A surrogate key is an artificial, system-generated identifier assigned to a record in a table. It is typically used as the primary key. It has no business meaning or semantic relationship to the real-world entity it represents. Common implementations include auto-incrementing integers or globally unique identifiers (GUIDs).

Surrogate keys exist purely to serve the needs of the database system: performance, stability, and simplicity.