Databases & Data Storage
Surrogate Key
Definition
A surrogate key is a unique identifier for a record in a database that has no business meaning. It is typically an auto-incrementing integer or a UUID (Universally Unique Identifier).
Why It Matters
Surrogate keys provide a simple, stable, and unique way to identify a record, regardless of any changes to the other data in the row. They simplify database design and make joins more efficient.
Contextual Example
Instead of using a combination of `FirstName`, `LastName`, and `DateOfBirth` as a primary key for a `Users` table (a "natural key"), it is much easier to add a single `UserID` column that is an auto-incrementing integer. This `UserID` is a surrogate key.
Common Misunderstandings
- A surrogate key is the opposite of a "natural key," which is a key that has a real-world, business meaning.
- Most modern database designs favor using surrogate keys for primary keys.