Transactions
August 29, 2024Database-Management-System
August 29, 2024Normalization
| Question 70 |
Consider the schema R = {S, T, U, V} and the dependencies
S → T, T → U, U → V and V → S If R = (R1 and R2)
be a decomposition such that R1 ∩ R2 = φ then the decomposition is
| not in 2NF | |
| in 2NF but not in 3NF | |
| in 3NF but not in 2NF | |
| in both 2NF and 3NF |
Question 70 Explanation:
Decomposition of a relation R into R1 and R2 is said to be lossless only if R1 ∩ R2 ≠ φ and the common attribute of R1 and R2 should be the primary key in any of the two decomposed relations(i.e.R1 and R2).
A relation which is in 2NF is always lossless.
In question, it is given that R1 ∩ R2 = φ which is violating lossless decomposition condition.
Hence the given relation R is not in 2NF.
A relation which is in 2NF is always lossless.
In question, it is given that R1 ∩ R2 = φ which is violating lossless decomposition condition.
Hence the given relation R is not in 2NF.
Correct Answer: A
Question 70 Explanation:
Decomposition of a relation R into R1 and R2 is said to be lossless only if R1 ∩ R2 ≠ φ and the common attribute of R1 and R2 should be the primary key in any of the two decomposed relations(i.e.R1 and R2).
A relation which is in 2NF is always lossless.
In question, it is given that R1 ∩ R2 = φ which is violating lossless decomposition condition.
Hence the given relation R is not in 2NF.
A relation which is in 2NF is always lossless.
In question, it is given that R1 ∩ R2 = φ which is violating lossless decomposition condition.
Hence the given relation R is not in 2NF.