AMCAT SQL and Database Concepts 3

Question 1

What is the primary purpose of an index in a database?

Accepted Answer

To speed up data retrieval operations at the cost of additional storage and slower writes

Answer

To enforce data integrity constraints

Answer

To encrypt data for security purposes

Answer

To automatically back up the database

Question 2

Which normal form eliminates transitive dependencies?

Accepted Answer

Third Normal Form (3NF)

Answer

First Normal Form (1NF)

Answer

Second Normal Form (2NF)

Answer

Boyce-Codd Normal Form (BCNF)

Question 3

What will the following query return?
SELECT name FROM Employees WHERE dept_id IN (SELECT dept_id FROM Departments WHERE location = 'Bangalore');

Accepted Answer

Names of employees who work in departments located in Bangalore

Answer

Names of employees who work in departments not located in Bangalore

Answer

Names of all employees regardless of location

Answer

An error because subqueries cannot be used with IN

Question 4

In a transaction, what does a SAVEPOINT allow you to do?

Accepted Answer

Roll back to a specific point within the transaction without undoing all changes

Answer

Commit the transaction permanently

Answer

Lock the entire database

Answer

Create a backup of the database

Question 5

Which of the following is true about a VIEW in SQL?

Accepted Answer

A view is a virtual table based on the result of a SELECT query

Answer

A view stores data physically in a separate table

Answer

A view cannot be used in a WHERE clause

Answer

A view automatically updates the underlying data when queried

Question 6

What is a deadlock in a database system?

Accepted Answer

When two or more transactions are waiting for each other to release locks, creating a circular dependency

Answer

When a query takes too long to execute

Answer

When a table exceeds its maximum row limit

Answer

When the database runs out of storage space