Consider a relation schema R(A, B, C, D, E), in which all attributes are…
2019
Consider a relation schema R(A, B, C, D, E), in which all attributes are atomic and single-valued. If A is the only candidate key in R, what is the highest normal form that can be guaranteed from the given information?
Answer: A. 2NF — Correct answer: 2NF Step 1: All attributes are atomic and single-valued, so the relation satisfies 1NF. Step 2: The only candidate key is A, which is a single…
- A.
2NF
- B.
BCNF
- C.
1NF
- D.
3NF
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Correct answer: A
Correct answer: 2NF
Step 1: All attributes are atomic and single-valued, so the relation satisfies 1NF.
Step 2: The only candidate key is A, which is a single attribute. Therefore, there cannot be a partial dependency on part of a composite key, so 2NF is satisfied.
Why not BCNF? BCNF requires every non-trivial functional dependency X → Y to have X as a superkey. The fact that A is a superkey only covers dependencies with determinant A; it does not rule out other dependencies such as B → C. Hence BCNF is not guaranteed from the given information.