Define : Surrogate Key

Surrogate key is a substitution for the natural primary key in Data Warehousing.

It is just a unique identifier or number for each row that can be used for the primary key to the table.

The only requirement for a surrogate primary key is that it is unique for each row in the table.

It is useful because the natural primary key can change and this makes updates more difficult.

Surrogated keys are always integer or numeric.