What are NoSQL databases and when to use them?

Madhavi Imashi
3 min readMay 15, 2022

Hey folks, Today we shall discuss what are NoSQL databases(non-relational databases) and the specialties of NoSQL databases compared to other relational data management systems which we also called SQL databases(RDBMS).

NoSQL databases (aka “not only SQL”) have become an emerging technology with rapid usage among developers nowadays because of the newer and awesome characteristics of NoSQL database systems.

There’s a set of different types of NoSQL databases as below which differ from one another from the unique data model of each type:

1. Wide-column stores — These databases store data in tables, rows, and dynamic columns which are flexible and can be spread across multiple servers.

2. Graph databases — These databases uses graph structures to represent and store data in nodes and edges, and properties. Nodes typically store information about different entities like people, places, and things, while edges store information about the relationships between those nodes.

3. Document databases These databases store data in documents. Documents are similar to JSON(Javascript Object Notation) objects. Each document contains pairs of fields and values.

4. Key-value databases — These databases are a little bit similar to document databases where each data is stored as a collection of key-value pairs. The keys serve as unique identifiers.

If we just try to get an overall high-level understanding of NoSQL, there’re some special features in all of these NoSQL databases, which are quite unique compared to other database types. NoSQL databases use a data model which is very different from the traditional row-and-column table models in RDBMS. Also, these DBMSs can be identified as more flexible, and scalable in terms of extendibility and usage. These benefits of using NoSQL databases can be narrowed down as below.

  • Flexible schemas — as in relational databases, non-relational data management system does not require a fixed schema.
  • Horizontal scalable — as NoSQL databases support a flexible schema model, they are designed to scale horizontally across multiple servers. (we can have the same instance running on different servers, different regions)
  • Fast queries due to the data model — typically the data is stored in a way that is optimized for queries. So the queries are fast compared to the query execution in relational databases.
  • Ease of use for developers. — easy to update and handle data and is very developer-friendly.

After all, what key features should you consider when deciding the best database type to be used for a project that you’re going to work on in the future?

Ok, the following factors can be taken into consideration to determine whether it is good to use NoSQL as the primary database model for your project.

  • volume of data to be stored is huge.
  • Requirements for scaling out the architecture.
  • Good for modern app-development architectures like microservices & real-time streaming.
  • Fast-paced agile development.
  • Storage of structured and semi-structured data.
  • The scale of traffic and the need for zero downtime can be handled by NoSQL databases whereas SQL databases find it difficult.
  • Also, new application paradigms can be more easily supported.

When considering all these factors and benefits, it is undoubtable that NoSQL databases will be always a good choice in terms of handling big data.

Out of the prevailing NoSQL database management systems, MongoDB is a popular document-based database that has the same set of features that we discussed above and many more as well.

Hope you got an understanding of the key characteristics of NoSQL databases and the benefits of using NoSQL databases. See you soon with a new blog post. TYIA:)

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