1. 口袋数据库：
PouchDB 是一个开源的 NoSQL 内联数据库。它是在 CouchDB 之后设计的，CouchDB 是一个支持 npm 的 NoSQL 数据库。它是用 JavaScript 语言编写的。由于 PouchDB 驻留在浏览器中，因此无需通过网络执行查询，因此速度非常快。它在浏览器中使用 IndexedDB 和 WebSQL 在本地存储数据。
2. PostgreSQL :
PostgreSQL 是一个强大的开源对象关系数据库系统。由于其高稳定性，它以低维护工作提供良好的性能。 PostgreSQL 是第一个实现多版本并发控制 (MVCC) 功能的 DBMS。
PouchDB 和 PostgreSQL 的区别
| SR.NO | PouchDB | PostgreSQL |
|---|---|---|
| 1 | It is developed by Apache Software Foundation. | It is developed by PostgreSQL Global Development Group . |
| 2 | It was released in 2012. | It was released in 1989. |
| 3 | It is written using Javascript language. | It is written in C language.. |
| 4 | The primary database model for PouchDB is Document Store. | The primary database model for PostSQL is Relational DBMS. |
| 5 | PouchDB server operating systems are server-less, requires a JavaScript environment (browser, Node.js). | PostgreSQL server operating systems are FreeBSD, HP-UX, Linux, NetBSD, OpenBSD, OS X, Solaris, Unix and Windows. |
| 6 | It does not supports predefined data types. | It supports predefined data types such as string, integer, float or date. |
| 7 | In PouchDB, partitioning can be done by Sharding. | In PostgreSQL, partitioning can be done by range, list and hash. |
| 8 | It does not supports SQL query language. | It supports SQL query language. |