Database-Management-System

Question 458

Which of the following statements is TRUE?

D₁ : The decomposition of the schema R(A, B, C) into R₁(A, B) and R₂ (A, C) is always lossless.

D₂ : The decomposition of the schema R(A, B, C, D, E) having AD → B, C → DE, B → AE and AE → C, into R₁ (A, B, D) and R₂ (A, C, D, E) is lossless.

A	Both D1 and D2
B	Neither D1 nor D2
C	Only D1
D	Only D2

Database-Management-SystemFunctional-DependencyUGC NET CS 2016 July- paper-3

Question 458 Explanation:

Statement(1) is incorrect because functional dependencies of relation R are not given, so we can’t say whether the decomposition of R into R1 and R2 is lossless or not.

Correct Answer: D

Question 458 Explanation:

Statement(1) is incorrect because functional dependencies of relation R are not given, so we can’t say whether the decomposition of R into R1 and R2 is lossless or not.