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What is relational database? What is the non-relational database?

What’s the difference between them? What brings NoSQL in the market? Which one is the best for your application?

That’s what we will talk about in this article :)

The relational database or SQL(Structured Query Language) database or relational data model that organizes and stores data in fixed schema. every table has a schema that defines the columns, data types and constraints.

The way relational databases store data as rows in a table. rows are made of up columns like the next figure

Tables can be related to each other by relations to extract related data from them.

The most popular relational databases are Oracle, MySQL, SQL Server, SQLite..

Non relational database or NoSQL database or document model structure that means data has no defined schema. every collection (table in SQL database) has multiple documents ( rows in SQL database) can be structured differently. document databases are schema-free. it lets you evolve your schema as you need like the next figure

The way non-relational databases varies in many ways: it can be column-oriented, document-oriented, graph-based, a Key-Value store. you can know more about these ways by next video

MongoDB is one of the most popular non-relational database.

The question is what brings non-relational or NoSQL database to the market?

The answer is rapid changing in the nature of data and big data revolution has shown some weaknesses in the traditional database.

So now let’s dive more into the strengths and weaknesses between them :)

The main pros in NoSQL database is flexibility that allows you to create documents without having to first define their structure. In SQL you should have predefined table schema and all data will be subjected to this schema but in NoSQL every document has its own unique structure and data types.

SQL allows combining different tables to extract related information, to manage the data together with relations between them but in NoSQL, poor or non-existent support for relations between objects. any relationships between your documents is something you must implement yourself.

In most situations, SQL databases are vertically scalable (scale-up), which means that you can increase the load on a single server by increasing things like CPU, RAM or SSD. NoSQL databases, on the other hand, are horizontally scalable (scale-out). This means that you handle more traffic by sharding or adding more servers in your NoSQL database. It’s like adding more floors to the same building versus adding more buildings to the neighborhood. NoSQL allows you to distribute large amounts of information using horizontal scaling without problems while scaling-out SQL database is more complicated. You can do it, but it’s hard and expensive. Scale-out is a fundamental design goal with document databases.

A NoSQL database is designed for fast performance with high volumes of data because of their easy structure compared to SQL databases.

So now the question is which is better??

There is no clear answer for this question cause it really depends entirely on your application and business you develop. But we can put it in some points that may help you to take your decision.

For business that need to store predictable, structured data with a finite number of users accessing it or require multi-row transactions like an accounting system then go with a Relational Database. It offers a level of maturity and widespread support.

If your business is experiencing massive growth that would require more servers, if you’re working with data that’s rapidly changing, or has a variety of data types and high traffic volume like social networks or real-time analytics or content management systems then go with Non-Relational Database. It offers a great performance and speed for this type of applications.

Hope this article shows some key points of relational and non-relational databases. If you think of any other key points that could be mentioned in this comparison, please suggest it in the comment section, it will be appreciated if you share it with us :)