A NoSQL database, where NoSQL stands for ‘Not only SQL’, is a distributed database. In a NoSQL database, unstructured data is stored across multiple servers (cluster of machines).
NoSQL databases have the following features:
- NoSQL datastores can store and handle huge volumes of data. NoSQL datastores can store both structured, semi-structured and unstructured data.
- They provide horizontal scalability, i.e., additional storage can be created easily by adding new nodes to a cluster, without taking the cluster offline.
- They follow not a strict schema but a flexible one that can be changed dynamically.
- They generally use commodity machines for the servers. This lowers the processing and storage cost per gigabyte in NoSQL databases as compared with that in SQL databases.