Which rule state that 'no component of a primary key can accept a NULL value'? MCQ with Answer and Explanation

Question

Share Report Error

Which rule state that 'no component of a primary key can accept a NULL value'?

A. Security Integrity Rule

B. Entity Integrity Rule

C. Referential Integrity Rule

D. Domain Constraint Rule

Answer: Option B

Solution (By JKSSB Mock Tests)

The Entity Integrity Rule states that a primary key column cannot contain NULL values, ensuring each row can be explicitly identified.

This question belongs to: Computer Database Management System (DBMS)

Request complete Subject PDF

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Database Management System (DBMS) Questions

Question #1

Which SQL function returns the current date and time?

A. CURDATE()

B. All of the above depending on the DBMS

C. NOW()

D. GETDATE()

View Answer & Solution Discuss

Get Complete Subject PDF for Computer

Correct Answer: Option B

Explanation:
Different DBMSs have different functions: MySQL NOW(), SQL Server GETDATE(), etc. But all return current date/time.

This question belongs to: Computer Database Management System (DBMS)

Question #2

Which of the following is a DML statement?

A. ALTER

B. UPDATE

C. CREATE

D. DROP

View Answer & Solution Discuss

Get Complete Subject PDF for Computer

Correct Answer: Option B

Explanation:
UPDATE is a Data Manipulation Language (DML) command used to modify existing records in a table. CREATE, ALTER, DROP are DDL.

This question belongs to: Computer Database Management System (DBMS)

Question #3

The actual collection of data tuples stored in a table at any specific point in time is called a what?

A. Relation Degree

B. Relation Domain

C. Relation Instance

D. Relation Schema

View Answer & Solution Discuss

Get Complete Subject PDF for Computer

Correct Answer: Option C

Explanation:
A Relation Instance is the specific collection of data rows (tuples) present in a table at a given moment. It changes frequently as data is modified.

This question belongs to: Computer Database Management System (DBMS)

Explore All Database Management System (DBMS) MCQs