Consider a relation R(ABCDE) with the FD set F = {A→BC, CD→E, B→D, E→A}…
Consider a relation R(ABCDE) with the FD set
F = {A→BC, CD→E, B→D, E→A} decomposed into D={ABC, CDE}. Which of the following is true regarding the decomposition D?
Answer: C. It is neither lossless nor dependency preserving — Given R(ABCDE), F={A→BC,CD→E,B→D,E→A}, and D={ABC,CDE}: Lossless Check:Common attribute C does not act as a key in ABC or CDE.Decomposition is…
- A.
It is lossless but not dependency preserving
- B.
It is lossy but dependency preserving
- C.
It is neither lossless nor dependency preserving
- D.
It is both lossless and dependency preserving
Attempted by 42 students.
Show answer & explanation
Correct answer: C
Given R(ABCDE), F={A→BC,CD→E,B→D,E→A}, and D={ABC,CDE}:
Lossless Check:Common attribute C does not act as a key in ABC or CDE.Decomposition is lossy.Dependency Preservation Check:B→D and E→A are not preserved.Decomposition is not dependency preserving.