A prime attribute of a relation scheme R is an attribute that appears A) in all candidate keys of R. B) in some candidate key of R. C) in a foreign key of R. D) only in the primary key of R.

Official answer: B) in some candidate key of R.. Explanation: In relational database design and normalization theory: - A candidate key is a minimal superkey of a relation. - A prime attribute (or key attribute) is defined as any attribute that is part of at least one candidate key (i.e., appears in *some* candidate key of R). - A non-prime attribute is an attribute that does not belong to any candidate key. Therefore, a prime attribute appears in some candidate key of R, making option (B) correct.

D) only in the primary key of R.

Integrity Constraints and Normal Forms

GATE CSE 2014 Set 3 · Q22

MCQ1 markEasy

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A prime attribute of a relation scheme $R$ is an attribute that appears

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Official answer: B) in some candidate key of R.

Integrity Constraints and Normal Forms

In relational database design and normalization theory:

A candidate key is a minimal superkey of a relation.
A prime attribute (or key attribute) is defined as any attribute that is part of at least one candidate key (i.e., appears in *some* candidate key of $R$ ).
A non-prime attribute is an attribute that does not belong to any candidate key.

Therefore, a prime attribute appears in some candidate key of $R$ , making option (B) correct.

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This Integrity Constraints and Normal Forms previous year question is Q22 of the GATE CSE 2014 Set 3 paper. Find more GATE CSE PYQs on Integrity Constraints and Normal Forms in Databases, or browse all GATE CSE PYQs.

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Integrity Constraints and Normal Forms in GATE CSE

Integrity Constraints and Normal Forms has 30 GATE CSE PYQs across 20 papers from 2011 to 2026. 10 of them are 1-mark MCQs like this one, and it is the only one in GATE CSE 2014 Set 3.

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Independent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.