Data Processing Database Management Systems 3

Question 1

What is the purpose of database normalization?

Accepted Answer

To reduce data redundancy and improve data integrity

Answer

To increase storage space usage

Answer

To slow down query performance for security

Answer

To remove all indexes from tables

Question 2

Which SQL command permanently removes a table and all its data from a database?

Accepted Answer

DROP TABLE

Answer

DELETE FROM

Answer

TRUNCATE TABLE

Answer

REMOVE TABLE

Question 3

What is a view in SQL?

Accepted Answer

A virtual table based on the result of a SELECT query

Answer

A physical copy of a table stored on disk

Answer

A type of database backup file

Answer

A user interface for data entry

Question 4

What does the GROUP BY clause do in SQL?

Accepted Answer

Groups rows sharing a common value into summary rows for aggregate functions

Answer

Sorts query results in ascending order

Answer

Combines two tables into one

Answer

Filters rows before they are processed

Question 5

What is a NoSQL database?

Accepted Answer

A non-relational database that stores data in formats like documents, key-value pairs, or graphs

Answer

A database with no structured query language at all

Answer

A database that stores only numeric data

Answer

A relational database that does not use indexes

Question 6

What is a deadlock in database processing?

Accepted Answer

A situation where two or more transactions each hold locks needed by the other, causing indefinite waiting

Answer

A type of database crash caused by power failure

Answer

A query that returns zero results

Answer

An error caused by inserting duplicate primary keys