Practice Questions

Which clause is used to filter grouped data in SQL?

A. WHERE B. GROUP BY C. HAVING D. ORDER BY

What is the purpose of a PRIMARY KEY constraint?

A. Allows duplicate values B. Ensures uniqueness and NOT NULL C. Creates an index only D. Allows NULL values

Which Oracle tool provides a graphical interface for database development?

A. SQL*Loader B. RMAN C. Oracle SQL Developer D. Data Pump

What happens when you execute a COMMIT statement?

A. Undo changes B. Save changes permanently C. Lock tables D. Delete records

Which join returns all records from the left table and matched records from the right?

A. INNER JOIN B. RIGHT JOIN C. LEFT JOIN D. FULL JOIN

What is a Pluggable Database (PDB)?

A. A backup file B. A portable collection of schemas within a CDB C. A user account D. A SQL script