Databases MCQ with Answers

Databases MCQ with Answers

17) Which-one of the following statements about normal forms is FALSE

Answer is:

Loss less, dependency - preserving decomposition into BCNF is always possible

18) Consider a relation scheme R = (A, B, C, D, E, H) on which the following functional dependencies hold: {A —> B, BC ---> D, E, —> C, D —> Al . What are the candidate keys of R?

Answer is:

AEH, BEH, DEH

19) The following functional dependencies are given:
AB -> CD, AF —> D, DE --> F, C —> G, F —› E, G --> A
Which one of the following options is false?

Answer is:

{AE }+ = {ACDEFG}

20) Which one of the following statements is FALSE

Answer is:

A prime attribute can be transitively dependent on a key in a BCNF relation

21) Consider the following relational schemes for a library for a library database:
Book (Title, Author, Catalog_no, Publisher, Year, Price)
Collection (Title, Author, Catalog_no)
Which ofthe 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 schemes: Which of the following statements is true?

Answer is:

Book is in 2NF and Collection is in 3NF

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