Question

In a relation, if more than one attribute can have distinct values, such attributes are called ______.

• A. Primary Key
• B. Candidate Key
• C. Foreign Key
• D. Composite Key

Hint:

Remember: All Primary Keys are Candidate Keys, but not all Candidate Keys are selected as the Primary Key.
A relation can have multiple Candidate Keys but exactly one Primary Key.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
A candidate key is a set of one or more attributes that can uniquely identify a tuple in a relation. If multiple attributes or sets of attributes qualify for this role, they are referred to as candidate keys.

Step 2: Detailed Explanation:
1. Primary Key: The one chosen from candidate keys to uniquely identify rows.
2. Candidate Key: All possible attributes that could serve as a primary key.
3. Foreign Key: An attribute that links to a primary key in another table.
4. Composite Key: A primary key consisting of two or more attributes.

Step 3: Final Answer:
Such attributes are called Candidate Keys.