Question

What is the importance of primary key in a table? Explain with suitable example.

Answer 1

Importance of a primary key

1. It uniquely identifies every row in a table.
2. It prevents duplicate values and maintains data integrity.
3. It does not allow NULL values.
4. It helps establish relationships between tables.
5. It makes searching and referencing records easier.

Example: In a Student table, AdNo can be the primary key because every student has a unique admission number. Thus, the record with AdNo = 101 can be identified without confusion.