Question

A functional dependency X → Y is considered a transitive dependency if:

• A. X and Y are in separate tables
• B. Y is a candidate key
• C. X is a primary key
• D. There exists another attribute Z such that X → Z and Z → Y

Hint:

Transitive means indirect. X reaches Y through a middle attribute Z, giving X to Z and Z to Y.

Answer 1

The Correct Option is D

Step 1: A transitive dependency happens when a non key attribute depends on another non key attribute rather than directly on the key.

Step 2: Formally, X determines Y indirectly through a middle attribute Z. That is, \( X \rightarrow Z \) and \( Z \rightarrow Y \).

Step 3: By the transitivity rule this forces \( X \rightarrow Y \), but the path passes through Z, which is what makes it transitive.

Step 4: So the condition is the existence of such a Z. Answer is (D).