Question 6 - MCQ questions - Chapter 8 - Database Concepts

Last updated at April 16, 2024 by

Consider a table with following structure: Employee(Emp_id, Emp_name, Dept, Desig, basic) In this table which attribute can be used as a primary key?

(a) Emp_id

(b) Emp_name

(c) Dept

(d) Desig

 

Answer:

A primary key is an attribute which can uniquely identify the records in a relation/table.

Checking the options

  • (a) Emp_id - No two employees can have the same employee id, so it can be used as a primary key. 
  • (b) Emp_name - 2 or more employees can have the same name, so it cannot be used as a primary key.
  • (c) Dept - There could be more than 1 employee in a department, so it cannot be used as a primary key.
  • (d) Desig - There could be more than 1 employee with the same designation, so it cannot be used as a primary key.

From the above explanation, it is clear that only Emp_id can be used as a primary key .

So, the correct answer is (A)

Transcript

Consider a table with following structure: Employee(Emp_id, Emp_name, Dept, Desig, basic) In this table which attribute can be used as a primary key? (a) Emp_id (b) Emp_name (c) Dept (d) Desig A primary key is an attribute which can uniquely identify the records in a relation/table. Checking the options (a) Emp_id - No two employees can have the same employee id, so it can be used as a primary key. (b) Emp_name - 2 or more employees can have the same name, so it cannot be used as a primary key. (c) Dept - There could be more than 1 employee in a department, so it cannot be used as a primary key. (d) Desig - There could be more than 1 employee with the same designation, so it cannot be used as a primary key. From the above explanation, it is clear that only Emp_id can be used as a primary key. So, the correct answer is (A)

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