15 Top DBMS Interview Questions and Answers

DBMS stands for Database Management System and is used to create, update, and delete data from databases which are used a lot in the fields of full-stack & data science thus needing further questioning.

DBMS questions are generally asked in an interview to check your fundamentals.
They are trying to assess you on the following:

1. Theoretical understanding

2. Your ability to articulate points based on the theory

3. Practical implementation and understanding

4. Comfortability in conversing with the articulated points

A major change can be seen by learning the main DBMS interview questions and understanding them.

Q1 Define a database?

A database is a collection of efficiently stored and organized related data.

Q2 What is DBMS?

DBMS is application software that stores data inside a database in a structural format such as a table or a view or a schema, which provides easy access and helps in the retrieval, insertion, and deletion of data.

Q3 What is a File System?

A file system stores files on a hard medium eg. a hard disk or a floppy disk.

Q4 Security Advantages of DBMS over traditional file systems?

DBMS can do all the traditional tasks more efficiently while simultaneously providing network security, risk protection, and access control on your data.

Q5 Advantages of the DBMS approach over traditional file systems?

The main advantages of the DBMS approach are as follows

1. Inconsistency in data
2. Redundancy in data
3. Searching and sharing of said data
4. Maintaining Integrity and security of data
5. Data concurrency

Q6 Why learn SQL for DBMS?

Structured Query Language (SQL) is a database query language generally used for creation, reading, retrieval, updating, and deletion (CRUD) in relational databases, and thus learning it is crucial for operating on a database.

Q7 Why is Structured Query language & DBMS two of the most essential skills that a Data Scientist can have in his/her respective field?

SQL & DBMS are essential for data storage, DBMS is used for a database, and operations performed on the said database are through SQL. DBMS makes the excruciating & repetitive task of Data analytics easier by streamlining data into a structured format that is much easier to work with.


Q8 Define a database model?

A data model is the fundamental and logical structure of a database about how data will be handled & organized in it.

Q9 What are normalization & denormalization?

normalization of data is when the data stored in a database is not having any redundancy and inconsistent dependency.

Denormalization of data is the addition of redundant data which increases the performance of a database and riddance of complex data.

Q10 What is a sub-query?

A query contained in a query is known as a sub-query.

Q11 What are DDL, DML, and DCL in SQL?

DDL is the abbreviation of Data Definition Language. For example, CREATE, ALTER, DROP, and RENAME

DML is the abbreviation of Data Manipulation Language. For example, SELECT, INSERT, and UPDATE

DCL is the abbreviation of Data Control Language. For example, GRANT and REVOKE

Q12 What are transactions as used in the context of DBMS and what are acid properties? 

A transaction in a database is a set of commands that are to be executed as a whole or none at all. An example of such would be bank transactions.

ACID stands for atomicity, Consistency, Isolation, and Durability. ACID properties are a set and this set guarantees reliability of the transactions in a database.

Q13 What is CLAUSE in SQL?

A clause is the part of the query through which you can customize the queries about data.

Q14 What is a relationship in DBMS and what kinds of relationships are found in a DBMS?

An association amongst entities is known as a relationship and these are of 3 types One-To-one, One-To-many, and many-to-many.

Q15 What is the E-R model in DBMS?

E-R model (Entity-Relationship model) in DBMS is a concept composed of entity types and their relationship amongst them.

Remember this isn't an exhaustive list, but a list of some of the most important questions, these are meant to give an understanding of the types of questions asked.