Relation R (A, B, C, D, E, F) {A→B,C→DF, AC→E,D→F}. If the above relation is…
Relation R (A, B, C, D, E, F) {A→B,C→DF, AC→E,D→F}. If the above relation is decomposed into D (AB, CD, ACEF) then
stmt 1: This decomposition is lossy and preserves dependencies
stmt 2: This is loss less and preserves dependencies
stmt 3: It is BCNF
Then correct answer is
Answer: D. None — Lossless Join: lossless. Common attributes form superkeys in their respective relations. D1(AB), D2(CD), D3(ACEF): First compose D2 & D3 then D23 and D1…
- A.
stmt 1 and stmt 3 are true
- B.
stm2 is true
- C.
stmt 2 and stmt 3 are true
- D.
None
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Show answer & explanation
Correct answer: D
Lossless Join: lossless. Common attributes form superkeys in their respective relations. D1(AB), D2(CD), D3(ACEF): First compose D2 & D3 then D23 and D1
Dependency Preservation: Not fully preserved. Some FDs are not preserved in the decomposed relations.
the FDs not fully preserved are C→F, D→F
BCNF: The decomposition is in BCNF.