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Top 23+ NoSQL Interview Questions and Answers

25/Oct/2021 | 12 minutes to read


Here is a List of essential NoSQL Interview Questions and Answers for Freshers and mid level of Experienced Professionals. All answers for these NoSQL questions are explained in a simple and easiest way. These basic, advanced and latest NoSQL questions will help you to clear your next Job interview.

NoSQL Interview Questions and Answers

These interview questions are targeted for NoSQL databases. You must know answers to these frequently asked NoSQL interview questions to clear an interview. We have separate documents for different NoSQL databases like Cosmos DB, MongoDB and RDBMS like SQL Server, PostgreSQL, MySQL etc. We have included some NoSQL vs SQL interview questions for your better understanding.

1. What is a NoSQL database?

NoSQL DB or non-relational databases store the data differently than relational databases do. NoSQL databases provide easy scale and high performance for massive amounts of unstructured and rapidly changing data. A relational data can also be stored in a NoSQL database but differently than relational databases (SQL Server, PostgreSQL) do. NoSQL databases has different types (Document DB, Key-value database, Graph database etc) based on data model.
NoSQL database sometimes called as "Not only SQL" or "non-SQL" database can also handle a huge amount of highly structured data means they are not restricted to fixed data models like relational databases.

2. How to choose between non-relational (NoSQL) and relational (SQL) databases?

You can choose between NoSQL and SQL databases based on certain parameters as below.
    NoSQL database is best for:
    • massive amount, rapidly changing and unstructured data.
    • When data is schema agnostic.
    SQL or relational database is best for:
    • When data schema is maintained by application.
    • Relational data that logical structure and requirement can be identified in advance.
  • Scenarios - NoSQL is a good choice for Mobile apps, real-time analytics, IoT Apps, Database migration. RDBMS is good for Banking systems, finance systems, Inventory management, Transaction management systems.
  • Scalability - NoSQL databases provide scalability horizontally by sharding across multiple servers. RDBMS provides scalability vertically by increasing server load.
  • Data Model - Database can be of any type - Key value, columnar, document DB and graph database. The RDBMS database is in the form of tables of rows and columns and uses SQL to query data.
  • For more visit - NoSQL Database

3. What different types of NoSQL Databases are you aware of?

There are 4 most common types of NoSQL databases as below.

  • Key-value databases
  • Document databases
  • Wide-column or Column-family databases
  • Graph databases stores

4. What is a Key-Value store or Key-Value database?

Key/Value databases use the key-value pairs to store the data in a hash table. Key uniquely identifies the data. This is used to store data using appropriate hash functions. Key-Value is a good choice when you want to lookup some data based on key rather than performing joins over multiple tables of key values. For more visit key-value data store.

5. What is DocumentDB?

DocumentDB or Document database is a completely NoSQL database service that stores the data as schema-free JSON (JavaScript Object Notation) documents.
When you are working on some application that needs to handle data with changing schema or you are not sure about the data which you need to work with and how much data application needs to handle. You are also not sure about the structure of data. You also need scalability, low cost and fast deployment for your data. In all these scenarios we consider DocumentDB. There are many DocumentDB services as below.

6. What is the Column store database?

Columnar column-oriented, column-family databases store the data table in the form of columns rather than by rows. Columnar databases are optimized for fast retrieval of columns from databases similar to how RDBMS is optimized for fast retrieval of rows. Amazon Redshift, Apache Cassandra are the examples of columnar databases. Column-wide databases are typically used for analytical applications as Column-wide nature of storage helps to load less data with less Disk I/O requirements.
For more visit Columnar Database.

7. What is a Graph Database (GDB)?

Graph Database is a specialized, single-purpose database to store and navigate relationships. Graph database is derived from the concept of Graph where nodes are used to store entity information and edges store the relationships. Graph databases use cases include Credit card fraud detection, Social media analysis etc.
For more visit Graph Database and What is Graph Database.

8. What are the advantages of NoSQL?

NoSQL databases come with a lot of benefits when compared to RDBMS. This benefits list include:

  • NoSQL databases come with scale-out architecture instead of monolithic architecture. It helps to handle massive volumes of data efficiently.
  • NoSQL databases can store unstructured, semi-structured and structured data which is easier to understand and use by enterprise applications.
  • Developers can easily update the schema and fields. You can add any new document easily without affecting the existing structure.
  • NoSQL databases are developer friendly as they need less transformations before using them in the applications.
  • Many NoSQL databases not only support easy scale-out architecture but they also allow you to change the structure of the database with Zero Downtime.
For more about NoSQL benefits visit Advantages of NoSQL Databases.

9. What are the disadvantages of NoSQL Databases?

10. Explain some features of NoSQL Databases?

11. How to choses correct database between NoSQL and RDBMS?

12. What is Vertical and Horizontal Scaling?

13. What is Database Sharding?

14. How to scale a NoSQL database?

15. What is NoSQL - CAP Theorem?

16. What is Polyglot Persistence in NoSQL Space?

17. What do you understand about NoSQL Database Performance Tuning?

18. What are different approaches to query optimization in NoSQL DB?

Some General Interview Questions for NoSQL

1. How much will you rate yourself in NoSQL?

When you attend an interview, Interviewer may ask you to rate yourself in a specific Technology like NoSQL, So It's depend on your knowledge and work experience in NoSQL.

2. What challenges did you face while working on NoSQL?

This question may be specific to your technology and completely depends on your past work experience. So you need to just explain the challenges you faced related to NoSQL in your Project.

3. What was your role in the last Project related to NoSQL?

It's based on your role and responsibilities assigned to you and what functionality you implemented using NoSQL in your project. This question is generally asked in every interview.

4. How much experience do you have in NoSQL?

Here you can tell about your overall work experience on NoSQL.

5. Have you done any NoSQL Certification or Training?

It depends on the candidate whether you have done any NoSQL training or certification. Certifications or training are not essential but good to have.


We have covered some frequently asked NoSQL Interview Questions and Answers to help you for your Interview. All these Essential NoSQL Interview Questions are targeted for mid level of experienced Professionals and freshers.
While attending any NoSQL Interview if you face any difficulty to answer any question please write to us at Our IT Expert team will find the best answer and will update on the portal. In case we find any new NoSQL questions, we will update the same here.