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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Last Updated :
22 Mar, 2018
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