NoSQL Databases is also called as “Not Only SQL”. NoSQL does not prohibit the SQL (Structured query Language). It employs less Consistency model for storage and retrieval of data than traditional relational databases. Some of the NoSQL databases are completely non-relational, others avoid relational functionalities as Fixed table schemas and joins. Most of the NoSQL databases are highly optimized “Key-Value stores” or “tuple stores”, for simple insertion and retrieval operations. NoSQL approach started with the goal of simple schema design, horizontal scalability, higher performance & availability etc.
Types of NoSQL Databases?
We can classify the NoSQL databases on the basis of data model, these are as follows:
Wide-Column – HBase, BigTable, Apache Cassandra, Amazon SimpleDB, HyperTable
Document – MongoDB, CouchDB, CouchBase
Key-Value – DynamoDB, Riak, Redis, Voldemort
Graph – Neo4j, Virtuoso, Allegro