Data Manipulation Language (DML): Interactive Learning Quizzes

Question 1

Which of the following is NOT a valid data type for an SQL column?

Accepted Answer

Array

Answer

Integer

Answer

String

Answer

Boolean

Question 2

Which SQL statement is used to retrieve data from a database table?

Accepted Answer

SELECT

Answer

INSERT INTO

Answer

UPDATE

Answer

DELETE

Question 3

What is the purpose of the ORDER BY clause in an SQL statement?

Accepted Answer

To sort the results of a query

Answer

To filter the results of a query

Answer

To group the results of a query

Answer

To limit the number of results returned by a query

Question 4

What is the role of a database index?

Accepted Answer

To speed up data retrieval

Answer

To maintain data integrity

Answer

To enforce business rules

Answer

To provide data encryption

Question 5

Which of the following SQL commands is NOT used to modify data in a table?

Accepted Answer

SELECT

Answer

INSERT

Answer

UPDATE

Answer

DELETE

Question 6

Which command is used to insert a new row into a table?

Accepted Answer

INSERT

Answer

UPDATE

Answer

SELECT

Answer

DELETE

Question 7

What is the correct syntax to insert a record with three columns (ID, Name, Age) into the 'Students' table?

Accepted Answer

INSERT INTO Students (ID, Name, Age) VALUES (1, 'John Doe', 21)

Answer

INSERT INTO Students VALUES (1, 'John Doe', 21)

Answer

INSERT Students (ID, Name, Age) VALUES (1, 'John Doe', 21)

Answer

INSERT Students VALUES (1, 'John Doe')

Question 8

What is the purpose of the UPDATE command?

Accepted Answer

Modify existing records in a table

Answer

Add new records to a table

Answer

Delete records from a table

Answer

Retrieve data from a table

Question 9

What is the main purpose of a PRIMARY KEY in a database table?

Accepted Answer

To uniquely identify each record in the table

Answer

To ensure that all records in the table have a unique value for a particular column

Answer

To enforce referential integrity between tables

Answer

To improve the performance of queries

Question 10

What is the key difference between a clustered index and a non-clustered index in a database?

Accepted Answer

Clustered indexes are physically stored in the same order as the data, while non-clustered indexes are not

Answer

Non-clustered indexes are physically stored in the same order as the data, while clustered indexes are not

Answer

Clustered indexes are created on multiple columns, while non-clustered indexes are created on a single column

Answer

Non-clustered indexes are created on multiple columns, while clustered indexes are created on a single column

Question 11

What is the primary purpose of a transaction in SQL?

Accepted Answer

To group multiple SQL statements into a single unit of work, ensuring data consistency

Answer

To enforce data integrity

Answer

To improve query performance

Answer

To create a backup of the database

Question 12

What is the primary purpose of a FOREIGN KEY constraint in a database?

Accepted Answer

To enforce referential integrity by ensuring that related data exists in other tables

Answer

To create a unique index on a column

Answer

To ensure data consistency

Answer

To improve query performance

Question 13

Which SQL command is used to create a new record in a database table?

Accepted Answer

INSERT INTO

Answer

ALTER TABLE

Answer

UPDATE SET

Question 14

Which clause in an SQL UPDATE statement specifies the condition for updating records?

Accepted Answer

WHERE

Answer

SET

Answer

LIMIT

Answer

ORDER BY

Question 15

Which SQL command is used to permanently remove records from a database table?

Accepted Answer

DELETE

Answer

TRUNCATE

Answer

DROP

Answer

REMOVE

Question 16

Explain the difference between a primary key and a foreign key.

Accepted Answer

A primary key uniquely identifies a row in a table, while a foreign key references a primary key in another table, establishing a relationship between them.

Answer

A primary key is always numeric, while a foreign key can be any data type

Answer

A primary key is used for sorting data, while a foreign key is used for filtering

Question 17

What is the main purpose of a transaction in a database management system?

Accepted Answer

To ensure data integrity by treating a group of database operations as a single unit

Answer

To improve database performance

Answer

To allow multiple users to access the database simultaneously

Question 18

What is the primary role of indexes in a database table?

Accepted Answer

To enhance data retrieval speed by organizing data in a specific order

Answer

To enforce data integrity

Answer

To store metadata about the table

Question 19

Which of the following is a recommended practice for writing efficient SQL queries?

Accepted Answer

Use descriptive and meaningful column names

Answer

Always use the * wildcard to select all columns

Answer

Do not optimize for performance

Answer

Avoid using subqueries