In a relational data model, which one of the following statements is TRUE?
(A)
A relation with only two attributes is always in BCNF.
(B)
If all attributes of a relation are prime attributes, then the relation is in BCNF.
(C)
Every relation has at least one non-prime attribute
(D)
BCNF decompositions preserve functional dependencies
Answer: (A)
Explanation:
Option A: It is true to say that every binary relation is always in BCNF
Option B: This is false because it is not necessary to have a relation in BCNF if all the attributes are prime attributes. For example, R(A, B, C) with FD A -> C, B -> C, C -> A Here all the attributes are prime but it is not in BCNF.
Option C: No, it is not necessary to have at least one non-prime attribute in a relation
Option D: No, it is not necessary that every lossless BCNF decomposition is dependency preserving
Quiz of this Question
Please comment below if you find anything wrong in the above post