NoSQL Options Compared, March 19, 2013 A Developer's Look at the Primary NoSQL Options
Developer: Damien Katz, formerly of Lotus Notes
License Type: Apache Open Source
Operating System: Linux, Mac OS X, Windows
Implementation Language: Erlang
Initial Release: 2005
A pure open-source product, CouchDB is a mainstream NoSQL database that, like many of the other products here, uses JSON documents as its primary storage entity. CouchDB stores metadata about updates and data currency in the document itself, leaving the task of resolving updates to the application (which generally consists of merging changes into one document and discarding the other). This model enables CouchDB to avoid locking during writes — a feature that permits it to handle a large number of concurrent writers, without difficulty. CouchDB is one of the few products that offers master-master replication, which facilitates multisite deployments.