Relational databases that are widely used even at present only allows to store structured data. Later on, there was a need to work more and more with unstructured data. This was when NoSQL databases came about as a response to the Internet and the need for faster speed and the processing of unstructured data. NoSQL databases are preferred over relational databases because of their speed and flexibility in storing data. It does not store data in relations or tables that belong to a strict structure. Data can be stored in an ad-hoc manner and they allow to store and process high volumes of different kinds of data. NoSQL databases are capable of processing unstructured big data that’s generated by social media, IoT and others. Therefore, social platforms like Twitter, LinkedIn, Facebook, and Google for example makes use of NoSQL databases.
These are some of the advantages of NoSQL databases:
Higher scalability
Distributed
Lower costs
A flexible schema
Can process unstructured and semi-structured data
Has no complex relationships
Over time there were different types of NoSQL databases that were introduced:
Document databases store data in documents similar to JSON (JavaScript Object Notation) objects. Each document contains pairs of fields and values. The values can typically be a variety of types including things like strings, numbers, booleans, arrays, or objects.
Key-value databases are a simpler type of database where each item contains keys and values.
Wide-column databases store data in tables, rows, and dynamic columns.
Graph databases store data in nodes and edges. Nodes typically store information about people, places, and things, while edges store information about the relationships between the nodes.