Consider a relational table R that is in 3NF, but not in BCNF. Which one of…

GATE · 2020 · CS · Computer Science & IT

Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE ?

A.
R has a nontrivial functional dependency X→A, where X is not a superkey and A is a prime attribute.
B.
R has a nontrivial functional dependency X→A, where X is not a superkey and A is a non-prime attribute and X is not a proper subset of any key.
C.
R has a nontrivial functional dependency X→A, where X is not a superkey and A is a non-prime attribute and X is a proper subset of some key.
D.
A cell in R holds a set instead of an atomic value.

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