UTpaper

Free mock tests & test series

Question 55Asked in UGC NET Computer Science, June 2014 (Paper II & III, Selected Questions)

Consider the following relational schemas for a library database :

Consider the following relational schemas for a library database : Book (Title, Author, Catalog–No, Publisher, Year, Price) Collection (Title, Author, Catalog–no) with the following functional dependencies : I. Title, Author → Catalog–no II. Catalog–no → Title, Author, Publisher, Year III. Publisher, Title, Year → Price Assume (Author, Title) is the key for both schemas. Which one of the following is true?
  1. ABoth Book and Collection are in BCNF.
  2. BBoth Book and Collection are in 3 NF.
  3. CBook is in 2NF and Collection in 3 NF.
  4. DBoth Book and Collection are in 2 NF.
Show answerHide answer

Correct answer: (C) Book is in 2NF and Collection in 3 NF.

Explanation

2NF says that all the non-key attributes should depend the keys, partial dependency (an attribute is defined by a part of a composite key) is not allowed 3NF says that any dependency between non-key attribute should be cleared. BCNF says that all determinants in a table is key for every non trivial (no overlapping attributes) function. In the table book, (Title Author) identifies catalog-no. Which if turn identifies publisher and year further (publisher, Title, Year) identifies price. Now here the dependents are partially dependent on the key attributes on left hand side of (R). So the table book is in 2NF. In the table collection, (Title, Author) determines catalog-no., the only non-key attribute. So it is in 3NF as well as BCNF.

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

This is question 55 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.