1. MongoDB：
MongoDB 是一个开源的面向文档的数据库，用于大容量数据存储。它属于 NoSQL 数据库的分类。 NoSQL 工具意味着它不使用通常的行和列。 MongoDB 使用 BSON(文档存储格式)，这是一种二进制格式的 JSON 文档。
2. 沙发数据库：
Apache CouchDB 是一个开源的面向文档的 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 存储数据，使用 MapReduce 作为其查询语言的 JavaScript，以及用于 API 的 HTTP。它由 Apache 软件基金会开发，最初于 2005 年发布。它是用 Erlang 编写的。
MongoDB 和 CouchDB 的区别：
| S.NO. | MONGODB | COUCHDB |
|---|---|---|
| 1. | Developed By MongoDB, Inc on 2009. | Developed by Apache Software Foundation and initially released in 2005. |
| 2. | MongoDB is written in C++. | CouchDB is written in Erlang. |
| 3. | It is one of the most popular document stores available both as a fully managed cloud service and for deployment on self-managed infrastructure. | It is native JSON – document store inspired by Lotus Notes, scalable from globally distributed server-clusters down to mobile phones. |
| 4. | The primary database model for MongoDB is Document store. | The primary database model for CouchDB is Document Store. |
| 5. | There is no Secondary database models. | It has Document store as Secondary database models. |
| 6. | Server operating systems for MongoDB are Linux, OS X, Solaris and Windows. | Server operating systems for CouchDB are Android, BSD, Linux, OS X, Solaris and Windows. |
| 7. | It supports predefined data types such as string, integer, double, decimal, boolean or date. | It does not supports predefined data types. |
| 8. | It supports read-only SQL queries via the MongoDB Connector for BI. | It does not supports SQL query language. |
| 9. | It support only one replication methods – Master-master replication. | It support two replication methods – Master-master replication and Master-slave replication. |
| 10. | It supports In-memory capabilities. | It does not supports In-memory capabilities. |
| 11. | It support multi-document ACID Transactions with snapshot isolation. | It does not support to ensure data integrity after non-atomic manipulations of data. |