Question 13Asked in UGC NET Computer Science, June 2014 (Paper II & III, Selected Questions)

Which of the following statements is false?

  1. AAny relation with two attributes is in BCNF.
  2. BA relation in which every key has only one attribute is in 2NF.
  3. CA prime attribute can be transitively dependent on a key in 3NF relation.
  4. DA prime attribute can be transitively dependent on a key in BCNF relation.
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Correct answer: (D) A prime attribute can be transitively dependent on a key in BCNF relation.

Explanation

A relation is in BCNF, if and only if, every determinant is a candidate key i.e. the left hand side of every non trivial dependency is a super key or there is a trivial dependency or both. After 3NF, there may arise a situation that two candidate keys are having one attribute in common (overlapping) and this overlapping must be cleared to satisfy BCNF. A prime attribute (an attribute that is a part of a candidate key) can on depend on a super key. So a prime attribute cannot be transitively dependent on a key in BCNF relation. So the false statement is option (d).

From UGC NET Computer Science PYQ, June 2014 (Paper II & III, Selected Questions)

This is question 13 of UGC NET Computer Science PYQ, June 2014 (Paper II & III, Selected Questions). See all questions of this paper with answers, or attempt the paper as a timed online test to get your score and all-India rank.