surrogate key

(database)

A unique primary key generated by the RDBMS that is not derived from any data in the database and whose only significance is to act as the primary key.

A surrogate key is frequently a sequential number (e.g. a Sybase "identity column") but doesn't have to be. Having the key independent of all other columns insulates the database relationships from changes in data values or database design and guarantees uniqueness.

Some database designers use surrogate keys religiously regardless of the suitability of other candidate keys. However, if a good key already exists, the addition of a surrogate key will merely slow down access, particularly if it is indexed.

Compare: intelligent key.

This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

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intelligent key

References in periodicals archive

There is also a secondary question of whether things whose properties are recorded in a database should be identified by keys or by surrogate keys. A key is some unique combination of a thing's existing properties, whilst a surrogate key is a new property assigned as the thing enters the database, solely for the purpose of identifying it and for no other purpose.

KEY FEATURES OF THE ASSOCIATIVE MODEL

The initial data sets created off the acute care data may derive the surrogate key for an encounter record from a combination of patient account number and discharge date.

Changing the Rules in Enterprise Data Warehousing

As this implies a large scale implementation, surrogate keys are used to ensure the data warehouse expansion over time.

Optimal data architecture for an telemedicine analytic platform

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