CouchDB和PostgreSQL之间的区别

1. CouchDB：
Apache CouchDB是面向开源文档的NoSQL数据库，它使用多种格式和协议来存储，传输和处理其数据，它使用JSON来存储数据，使用JavaScript作为其使用MapReduce的查询语言以及使用HTTP作为API。它由Apache Software Foundation开发，最初于2005年发布。它是用Erlang编写的。

2. PostgreSQL：
PostgreSQL是一个功能强大的开源对象关系数据库系统。它具有较高的稳定性，因此可以在较低的维护工作量下提供良好的性能。 PostgreSQL是第一个实现多版本并发控制(MVCC)功能的DBMS。

CouchDB和PostgreSQL之间的区别：

S.NO.	COUCHDB	POSTGRESQL
1.	Developed by Apache Software Foundation and initially released in 2005.	Developed By PostgreSQL Global Development Group on 1989.
2.	It is native JSON – document store inspired by Lotus Notes, scalable from globally distributed server-clusters down to mobile phones.	It is widely used open source RDBMS.
3.	CouchDB is written in Erlang.	PostgreSQL is written in C languages.
4.	The primary database model for CouchDB is Document Store.	The primary database model for PostgreSQL is Relational DBMS.
5.	It does not supports SQL query language.	It supports SQL query language.
6.	Server operating systems for CouchDB are Android, BSD, Linux, OS X, Solaris and Windows.	Server operating systems for PostgreSQL are FreeBSD, HP-UX, Linux, NetBSD, OpenBSD, OS X, Solaris, Unix and Windows.
7.	It does not supports predefined data types.	It supports predefined data types such as string, integer, float or date.
8.	It does not support XML Format.	It supports XML Format.
9.	It support two replication methods – Master-master replication and Master-slave replication.	It support only one replication methods – Master-master replication.
10.	In CouchDB, partitioning can be done by Sharding.	In PostgreSQL, partitioning can be done by range, list and hash.