An instance of relational schema R (A, B, has distinct values of A including NULL values. Which one of the following is true?
A.A is a candidate key
B.A is not a candidate key
C.A is a primary Key
D.Both (A) and (C)
Answer:B
An instance of relational schema R (A, B, has distinct values of A including NULL values. Which one of the following is true?
A.A is a candidate key B.A is not a candidate key C.A is a primary Key D.Both (A) and (C)