Motivations for this approach include simplicity of design, horizontal scaling and finer control over availability. NoSQL databases are often highly optimized key–value stores intended for simple retrieval and appending operations, with the goal being significant performance benefits in terms of latency and throughput.
NoSQL databases are finding significant and growing industry use in big data and real-time web applications. NoSQL systems are also referred to as "Not only SQL" to emphasize that they do in fact allow SQL-like query languages to be used.
Most common NoSQL classifications:
- Column: Hbase, Accumulo
- Document: MongoDB, Couchbase
- Key-value : Dynamo, Riak, Redis, Cache, Project Voldemort
- Graph: Neo4J, Allegro, Virtuoso
See Row vs Columnar vs NoSQL Databases.
For a more complete list of the nearly 150 different NoSQL databases, with more standard classification, see http://nosql-database.org.