Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
| Question 282 |
Consider a schema R(A, B, C, D) and functional dependencies A→ B and C→ D. Then the decomposition of R into R1 (A, B) and R2(C, D) is
| lossless join but not dependency preserving | |
| dependency preserving but not lossless join | |
| not dependency preserving and not lossless join | |
| part dependency preserving and lossless join |
Question 282 Explanation:
The given decomposition is not lossless join because there is no common attributes between R1 and R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
Correct Answer: B
Question 282 Explanation:
The given decomposition is not lossless join because there is no common attributes between R1 and R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.
But the given decomposition is dependency preserving, A→ B is covered by R1 and C→ D is covered by R2.