Referential Integrity requires that for any foreign key attribute, the referenced relation must have a tuple with the
same value for which of the following?

A.
primary key

B.
secondary key

C.
foreign key

D.
candidate key

Explanation:
A foreign key is an attribute in one table that references or matches the primary key of another table. The
primary key is the attribute that is used to ensure that each row or tuple in a table unique. Together, the foreign
key and the primary key ensure referential integrity.
Incorrect Answers:
B: Secondary keys are candidate keys that have not been chosen as the primary key. The primary key is the
attribute that is used to make each row or tuple in a table unique. Candidate keys are a subset of attributes that
from which the database developer can choose the primary key.
C: A foreign key is an attribute in one table that matches the primary key of another table and is used to crossreference tables.
D: Candidate keys are a subset of attributes that from which the database developer can choose the primary
key to uniquely identify any tuple or record in a table.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 1174, 1179-1180,
1181
Stewart, James, Ed Tittel and Mike Chapple, CISSP: Certified Information Systems security Professional Study
Guide, 5th Edition, Wiley Publishing, Indianapolis, 2011, pp. 276, 312
http://databases.about.com/cs/specificproducts/g/candidate.htm
http://rdbms.opengrass.net/2_Database Design/2.1_TermsOfReference/2.1.2_Keys.html