Question

What is a primary key in a relational database?

• A. A unique identifier for each record in a table
• B. A key used for sorting records
• C. A key linking two tables
• D. A key for encrypting data

Hint:

Choose primary keys that are simple, unique, and unlikely to change (e.g., IDs).

Answer 1

The Correct Option is A

A primary key in a relational database:
- Uniquely identifies each record in a table.
- Ensures no duplicate or null values.
- Often used for referencing in other tables (foreign keys).
Option (2) relates to indexing, (3) to foreign keys, and (4) to security, none of which define a primary key.
Option (1) is correct.