A NoSQL database (also known as a non-relational database) is a database that does not store the data in predefined tables with rows and columns. That sounds very broad as it means just any way except the SQL way and that is because it is. There are many types of NoSQL databases, the most common being:
- Key-value databases. Very simple databases that just store a key and value pair. You can compare this to the localStorage in a browser.
- Document databases. These are databases that store data in documents that are similar to JSON objects.
- Graph databases. Stores the data the graph way using nodes and edges. The nodes define the data and the edges define the relations.
There are many more, as very specific use cases may call for a very specific way of storing the data. But for now, we will focus on the document databases type as unless you start working at a company with a specific use case, that will be how the data is being stored.
Have a look at the following video for a quick overview:
{% hyf-youtube src="https://www.youtube.com/watch?v=BgQFJ_UNIgw" %}
If you just can't get enough, here are some extra links that mentors/students have found useful concerning this topic: