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Data Models into Database Designs - Technical MCQs

Q1:

A unique, DBMS-supplied identifier used as the primary key of a relation is called a(n):

A primary key.

B foreign key.

C composite key.

D surrogate key.

ANS:D - surrogate key.

Surrogate keys are keys that have no “business” meaning and are solely used to identify a record in the table. Such keys are either database generated (example: Identity in SQL Server, Sequence in Oracle, Sequence/Identity in DB2 UDB etc. ) or system generated values (like generated via a table in the schema).