|
Apache CouchDB, commonly referred to as CouchDB, is an open source database that focuses on ease of use and on being "a database that completely embraces the web".〔(【引用サイトリンク】title=Apache CouchDB )〕 It is a document-oriented NoSQL database that uses JSON to store data, JavaScript as its query language using MapReduce, and HTTP for an API.〔 CouchDB was first released in 2005 and later became an Apache project in 2008. Unlike a relational database, CouchDB does not store data and relationships in tables. Instead, each database is a collection of independent documents. Each document maintains its own data and self-contained schema. An application may access multiple databases, such as one stored on a user's mobile phone and another on a server. Document metadata contains revision information, making it possible to merge any differences that may have occurred while the databases were disconnected. CouchDB implements a form of Multi-Version Concurrency Control (MVCC) in order to avoid the need to lock the database file during writes. Conflicts are left to the application to resolve. Resolving a conflict generally involves first merging data into one of the documents, then deleting the stale one. Other features include document-level ACID semantics with eventual consistency, (incremental) MapReduce, and (incremental) replication. One of its distinguishing features is multi-master replication, which allows it to scale across machines to build high performance systems. Administration is supported with a built-in web application called Futon. == History == CouchDB (''Couch'' is an acronym for ''cluster of unreliable commodity hardware'')〔(Exploring CouchDB ), article from IBM Developer Works〕 is a project created in April 2005 by Damien Katz, former Lotus Notes developer at IBM. Damien Katz defined it as a "storage system for a large scale object database". His objectives for the database were to become the database of the Internet and that it would be designed from the ground up to serve web applications. He self-funded the project for almost two years and released it as an open source project under the GNU General Public License. In February 2008, it became an Apache Incubator project and the license was changed to the Apache License.〔(Apache mailing list announcement ) on mail-archives.apache.org〕 A few months after, it graduated to a top-level project.〔(Re: Proposed Resolution: Establish CouchDB TLP ) on mail-archives.apache.org〕 This led to the first stable version being released in July 2010.〔("CouchDB NoSQL Database Ready for Production Use" ), article from PC World of Jully 2010〕 In early 2012, Damien Katz left the project to focus on Couchbase Server. Since Katz's departure, the Apache CouchDB project has continued, releasing 1.2 in April 2012 and 1.3 in April 2013. In July 2013, the CouchDB community merged the codebase for BigCouch, Cloudant's clustered version of CouchDB, into the Apache project. The BigCouch clustering framework is prepared to be included in an upcoming release of Apache CouchDB. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「CouchDB」の詳細全文を読む スポンサード リンク
|