Top interview questions | Practice Quiz, MCQ Questions | Solutions for interview

Question 1

Which of the following best describes an RDBMS?

1

A database system that organizes data in tables with relationships

2

A database system that only allows unstructured data storage

3

A database system that stores data in key-value pairs

4

A file-based system for data storage

Question 2

In a relational database, what does a foreign key do?

1

Automatically indexes data

2

Establishes a relationship between two tables

3

Ensures a table has at least one row

4

Uniquely identifies a row in a table

Question 3

Which of the following is an example of an RDBMS?

1

MySQL

2

MongoDB

3

Firebase

4

Neo4j

Question 4

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

1

To uniquely identify each row

2

To allow duplicate values

3

To create foreign keys

4

To store null values

Question 5

In a relational database, what does normalization help to achieve?

1

Increasing redundancy

2

Slowing down performance

3

Reducing redundancy

4

Increasing complexity

Question 6

What is the primary advantage of using a key-value store over a relational database?

1

Requires less storage space

2

Stronger ACID compliance

3

Better support for complex joins

4

Fast lookup and retrieval of data

Question 7

What is the primary disadvantage of key-value stores compared to relational databases?

1

Lack of complex query capabilities

2

Requires more memory

3

Does not support distributed systems

4

Poor performance for key lookups

Question 8

Which of the following is NOT an example of a key-value database?

1

PostgreSQL

2

Memcached

3

Cassandra

4

DynamoDB

Question 9

Which SQL statement is used to retrieve unique values from a column?

1

SELECT DIFFERENT column_name FROM table_name;

2

SELECT DISTINCT column_name FROM table_name;

3

SELECT UNIQUE column_name FROM table_name;

4

SELECT column_name FROM table_name WHERE DISTINCT;

Question 10

What does SQL stand for?

1

Standardized Query Logic

2

Structured Query Language

3

Sequential Query Language

4

System Query Language

Question 11

Which SQL command is used to remove all records from a table without deleting the table structure?

1

CLEAR

2

DELETE

3

TRUNCATE

4

DROP

Question 12

Which SQL join returns only the matching rows from both tables?

1

LEFT JOIN

2

FULL JOIN

3

INNER JOIN

4

RIGHT JOIN

Question 13

Which SQL constraint ensures that a column cannot have NULL values?

1

PRIMARY KEY

2

UNIQUE

3

CHECK

4

NOT NULL

Question 14

Which of the following is NOT an SQL aggregate function?

1

AVG()

2

SUM()

3

CONCAT()

4

COUNT()

Question 15

Which SQL clause is used to filter records from a table?

1

ORDER BY

2

HAVING

3

WHERE

4

GROUP BY

Question 16

Which SQL JOIN returns all records from the left table and only matching records from the right table?

1

INNER JOIN

2

LEFT JOIN

3

FULL JOIN

4

RIGHT JOIN

Question 17

Which constraint is used to ensure that all values in a column are unique?

1

UNIQUE

2

FOREIGN KEY

3

NOT NULL

4

CHECK

Question 18

Which SQL clause is used with aggregate functions to group results?

1

GROUP BY

2

ORDER BY

3

DISTINCT

4

HAVING

Question 19

Which database index type speeds up text searches in SQL?

1

Full-Text Index

2

Hash Index

3

Clustered Index

4

B-Tree Index

Question 20

Which SQL command is used to permanently save changes in a transaction?

1

DELETE

2

COMMIT

3

SAVEPOINT

4

ROLLBACK

Question 21

Which normal form removes partial dependency?

1

BCNF

2

2NF

3

1NF

4

3NF

Question 22

Which index type does MySQL use by default for primary keys?

1

Full-Text Index

2

Bitmap Index

3

Hash Index

4

B-Tree Index

Question 23

Which SQL command creates a virtual table?

1

CREATE PROCEDURE

2

CREATE VIEW

3

CREATE TABLE

4

CREATE INDEX

Question 24

Which keyword is used to define an output parameter in an SQL stored procedure?

1

OUTPUT

2

OUT

3

RESULT

4

RETURN

Question 25

Which ACID property ensures that once a transaction is committed, it remains so even in case of system failure?

1

Atomicity

2

Isolation

3

Durability

4

Consistency

Question 26

What is the main goal of normalization in a database?

1

To minimize redundancy and improve data integrity

2

To reduce data integrity

3

To increase redundancy

4

To store data in a single large table

Question 27

What does ACID stand for in DBMS?

1

Access, Control, Integrity, Data

2

Atomicity, Consistency, Isolation, Durability

3

Automation, Control, Integrity, Dependency

4

Accuracy, Consistency, Isolation, Database

Question 28

Which of the following is NOT a type of database model?

1

Hierarchical

2

Linear

3

Network

4

Graph-based

Question 29

Which of the following SQL commands is used to remove all records from a table but keep its structure?

1

ALTER

2

DROP

3

TRUNCATE

4

DELETE

Question 30

Which of the following is an advantage of NoSQL databases over traditional RDBMS?

1

Schema flexibility

2

Better horizontal scalability

3

Handling unstructured data

4

All of the above