B.S.W.E. Bachelor of Software Engineering Database Systems & SQL 2

Question 1

What is a database index and what does it improve?

Accepted Answer

A data structure that improves query performance

Answer

A list of all tables

Answer

A backup of the database

Answer

A primary key constraint

Question 2

What does the GROUP BY clause do in SQL?

Accepted Answer

Groups rows sharing a common value for aggregate functions

Answer

Sorts results in ascending order

Answer

Filters rows based on conditions

Answer

Joins multiple tables

Question 3

What is a stored procedure in SQL?

Accepted Answer

A precompiled set of SQL statements stored in the database

Answer

A backup procedure for the database

Answer

A trigger that fires on data changes

Answer

A view that stores query results

Question 4

What is the difference between WHERE and HAVING in SQL?

Accepted Answer

WHERE filters before grouping; HAVING filters after grouping

Answer

WHERE is for strings; HAVING is for numbers

Answer

WHERE is used with JOINs; HAVING is not

Answer

They are interchangeable

Question 5

What is a database view?

Accepted Answer

A virtual table based on a SELECT query

Answer

A physical table storing data

Answer

A database entity-relationship diagram

Answer

A stored procedure without parameters

Question 6

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)