Introduction
NoSQL databases are commercial as well as open source database management software supporting massive data storage across distributed servers. Some of the NoSQL support SQL or SQLlike query language, hence to avoid the misunderstanding that SQL cannot be used, NoSQL is redefined as ‘‘Not Only SQL’’.
The following three are the major contributors of the NoSQL movement :
1. BigTable (Google) started in 2004 by Google.
2. Dynamo: Amazon’s Highly Available Key-value Store.
3. CAP theorem.