Question

Consider the following relation:
STUDENT

RollNumber	Name	Class	Date of Birth	Address

What should be the primary key for relation STUDENT? 
The primary key for the STUDENT relation should be the RollNumber, as it uniquely identifies each student in the table.

• A. Class
• B. RollNumber
• C. DateofBirth
• D. Address

Hint:

Primary keys must be unique and not null. "RollNumber" fits both criteria.

Answer 1

The Correct Option is B

To determine the primary key for the STUDENT relation, we must select a field that uniquely identifies each record in the table. Let’s evaluate each option:

1. Class: Multiple students can belong to the same class, so this is not unique.
2. RollNumber: Typically, each student is assigned a unique roll number. Thus, it can uniquely identify each student.
3. Date of Birth: Multiple students can share the same date of birth, so this is not distinct.
4. Address: Students may live at the same address, so this is not unique.

Since the RollNumber uniquely identifies each student, it should be the primary key for the STUDENT relation.