各种 NoSQL 的比较
NoSQL 与 NoSQL 之间的区别，要远大于不同的 SQL 数据库之间的区别，所以软件架构师必须要在项目一开始就选好一款合适的 NoSQL。
即使关系型数据库依然是非常有用的工具，但它们持续几十年的垄断地位就要走到头了。现在已经存在无数能撼动关系型数据库地位的 NoSQL，当然，这些 NoSQL 还无法完全取代它们。（也就是说，关系型数据库还是处理关系型事务的最佳方式。）
NoSQL 与 NoSQL 之间的区别，要远大于不同的 SQL 数据库之间的区别，所以软件架构师必须要在项目一开始就选好一款合适的 NoSQL。
考虑到这种情况，，本文为大家介绍以下几种 NoSQL 之间的区别：Cassandra, Mongodb, CouchDB, Redis, Riak, Couchbase (ex-Membase), Hypertable, ElasticSearch, Accumulo, VoltDB, Kyoto Tycoon, Scalaris, Neo4j和HBase：
最流行的 NoSQL MongoDB 2.2版开发语言： C++
主要特性： 保留 SQL 中一些用户友好的特性（查询、索引等）
许可证： AGPL （驱动: 采用Apache许可协议）
数据传输格式： 自定义，二进制（ BSON 文档格式）
应用场景：
使用案例：
想布署 MySQL 或 PostgreSQL，但预先定义数据字典让你望而却步。这个时候，MongoDB 是你可以考虑的选项
MongoDB 的详细介绍：请点这里
MongoDB 的下载地址：请点这里
推荐阅读：
CentOS 6 使用 yum 安装MongoDB及服务器端配置
Ubuntu 13.04下安装MongoDB2.4.3
如何在MongoDB中建立新数据库和集合
MongoDB入门必读(概念与实战并重)
《MongoDB 权威指南》(MongoDB: The Definitive Guide)英文文字版[PDF]
Riak 1.2版开发语言： Erlang、C、以及一些 JavaScript
主要特性： 容错机制（当一份数据失效，服务会自动切换到备份数据，保证服务一直在线 —— 译者注）
许可证： Apache
数据传输格式： HTTP/REST 架构，或自定义二进制格式
应用场景：
使用案例：
销售点数据收集；工厂控制系统；必须实时在线的系统；需要易于升级的网站服务器
CouchDB 1.2版开发语言： Erlang
主要特性： 数据一致性；易于使用
许可证： Apache
数据传输格式： HTTP/REST
应用场景：
使用案例：
可用于客户关系管理（CRM），内容管理系统（CMS）；可用于主主互备甚至多机互备
更多详情见请继续阅读下一页的精彩内容：
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