NoSQL means Not only SQL.
NoSQL databases have their roots in the open source community.
NoSQL database implementations are technically different from each other.
Adopting NoSQL databases has several benefits, including storing and retrieving session information and event logging for apps.
The four main categories of NoSQL databases are Key-Value, Document, Wide Column, and Graph.
Key-value NoSQL databases are the least complex architecturally.
Document-based NoSQL databases use documents to make values visible for queries.
In document-based NoSQL databases, each piece of data is considered a document, which is typically stored in either JSON or XML format.
Column-based databases spawned from the architecture of Google’s Bigtable storage system.
The primary use cases for column-based NoSQL databases are event logging and blogs, counters, and data with expiration values.
Graph databases store information in entities (nodes) and relationships (edges).