X is called as of Y for a relation X- Y
Optym technical mcq question, verified with a worked answer. Free to practise - no sign-up.
X is called as ____ of Y for a relation X->Y
Show answer & explanation
Answer: A. A) Super key
In relational database theory, if X functionally determines all attributes Y of a relation (X -> Y), then X contains a candidate key and is called a Super key.
Step-by-step Derivation:
Step 1: A functional dependency X -> Y states that X uniquely determines Y.
Step 2: When X determines all attributes Y of the relation schema, X is a super key of the relation.
Step 3: Hence X is called a Super key.