What is a database lock? MCQ with Answer and Explanation

What is a database lock?

A. A user account

B. A backup file

C. A type of index

D. A mechanism to prevent simultaneous access to the same data causing inconsistency

Answer: Option D

Locking is a concurrency control mechanism that ensures data integrity during simultaneous transactions.

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

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Question #1 Report Error

Which normal form eliminates all transitive dependencies?

A. 1NF

B. 2NF

C. 3NF

D. BCNF

Correct Answer: Option C

Explanation:
Third Normal Form (3NF) eliminates transitive dependencies, where non-key attributes depend on other non-key attributes.

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

Question #2 Report Error

Which of the following is a valid constraint in SQL?

A. FOREIGN KEY

B. PRIMARY KEY

C. CHECK

D. All of the above

Correct Answer: Option D

Explanation:
CHECK, PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL are all constraints in SQL.

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

Question #3 Report Error

Which of the following is a DCL (Data Control Language) command?

A. GRANT

B. COMMIT

C. SELECT

D. CREATE

Correct Answer: Option A

Explanation:
GRANT and REVOKE are DCL commands. COMMIT is TCL, SELECT is DML, CREATE is DDL.

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