ISRO | ISRO CS 2017 | Question 15

Consider the following table : Faculty (facName, dept, office, rank, dateHired)

facName	dept	office	rank	dateHired
Ravi	Art	A101	Professor	1975
Murali	Math	M201	Assistant	2000
Narayanan	Art	A101	Associate	1992
Lakshmi	Math	M201	Professor	1982
Mohan	CSC	C101	Professor	1980
Lakshmi	Math	M201	Professor	1982
Sreeni	Math	M203	Associate	1990
Tanuja	CSC	C101	Instructor	2001
Ganesh	CSC	C105	Associate	1995

(Assume that no faculty member within a single department has same name. Each faculty member has only one office identified in office). 3NF refers to third normal form and BCNF refers to Boyee-Codd Normal Form

Then Faculty is

(A) Not in 3NF, in BCNF
(B) In 3NF, not in BCNF
(C) In 3NF, in BCNF
(D) Not in 3NF, not in BCNF


Answer: (B)

Explanation: There are two non-trivial functional dependencies (FD) in given table:

facName → dept, office, rank, datehired
office → dept

Given, Each faculty member has only one office identified in office, that means facName is the primary key (so superkey).

Therefore, FD facName → dept, office, rank, datehired is in 3 NF as well as in BCNF, because facName is the primary key. But FD office → dept is not in BCNF because office is not superkey but dept is in 3 NF as dept is the prime attribute because {dept, rank} is super key.

So, overall relation Faculty is in 3 NF but not in BCNF.

Option (B) is correct.

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