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39 votes
39 votes

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

  1. in all candidate keys of $R$
  2. in some candidate key of $R$
  3. in a foreign key of $R$
  4. only in the primary key of $R$

4 Answers

Best answer
29 votes
29 votes
Answer (B).

The attributes of a candidate key are called the prime attributes. Suppose $ABC$ is one candidate key of a Relation $R(ABCDEFGH).$ Then the attributes $A, B$ and $C$ all are prime attributes. Similarly if $ABD$ is also another candidate key in the same relation $R,$ then $D$ is also a prime attribute. And conversely, an attribute that does not occur in ANY candidate key is called a non-prime attribute.
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54 votes
54 votes

Prime attribute is a constituent of a candidate key. it need not present in all candidate keys. Hence, option B is correct.

Correct me if i went wrong.

–6 votes
–6 votes

(A) in all candidate keys of $R$

a prime attribute need not be necessaryly in the primary key alone, though attributes in all the candidate key are considered prime attribute

Answer:

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