Question

The table below is an attribute table about employee records. Which attribute can be used as a primary key?

Employee	Name	Designation	Department
(Emp_ID)	(Emp_Name)	(Emp_Desig)	(Emp_Dept)
100260	Prashant	Software Developer	Information Technology
100265	Dinesh	Junior Engineer	Embedded System
100252	Somya	HR Manager	Management
100271	Dinesh	Junior Engineer	Information Technology

 

• A. \( {Emp\_Name} \)
• B. \( {Emp\_ID} \)
• C. \( {Emp\_Dept} \)
• D. \( {Emp\_Desig} \)

Hint:

When identifying a primary key, look for an attribute that is {never repeated} and can {uniquely identify each row}. IDs are often used as primary keys for this reason.

Answer 1

The Correct Option is B

A primary key is an attribute (or a set of attributes) that uniquely identifies each record in a database table. From the table:

Emp_Name is not unique (e.g., "Dinesh" appears twice),
Emp_Desig and Emp_Dept are also repeated for different employees,
Emp_ID, however, is unique for each row, making it the only suitable attribute to be a primary key.

Hence, the correct answer is Emp_ID.