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.微软SQL服务器：
Microsoft SQL Server 是由 Microsoft Corporation 开发并于 1989 年 4 月 24 日首次发布的关系数据库管理系统 (RDBMS)。它是用 C 和 C++ 语言编写的。它依赖于平台，并且是基于 GUI 和 CLI 的软件。它支持企业环境中的各种事务处理、分析应用程序和商业智能。
PouchDB 和 MS SQL Server 的区别：
| S.NO. | PouchDB | MS SQL Server |
|---|---|---|
| 1. | It was developed by Apache Software Foundation. | It was developed by Microsoft Corporation. |
| 2. | PouchDB was initially released in 2012. | MS SQL Server was initially released on April 24, 1989. |
| 3. | PouchDB is written using Javascript language. | MS SQL Server is developed in C and C++. |
| 4. | PouchDB is server-less. It requires a JavaScript environment (browser, Node.js). | For MS SQL Server, server operating systems are Linux and Windows. |
| 5. | PouchDB provides us with Eventual Consistency method to ensure consistency in a distributed system. | MS SQL Server provides us with Immediate Consistency method to ensure consistency in a distributed system. |
| 6. | In PouchDB there are no predefined datatypes. | MS SQL Server has predefined datatypes such as float, date, etc. |
| 7. | In PouchDB primary database model is Document Store. | In MS SQL Server primary database model is Relational DBMS. |
| 8. | PouchDB supports both Master-Slave Replication and Master-Master Replication. | MS SQL Server supports Replication but depending on the SQL-Server Edition. |
| 9. | PouchDB does not support concurrent manipulation of data. | MS SQL Server supports concurrent manipulation of data. |
| 10. | The license for PouchDB is open-sourse. | The license for MS SQL Server is commercial. |
| 11. | PouchDB does not support XML data format. | MS SQL Server supports XML data format. |
| 12. | Some companies like GenCorp Technologies, Akamai Technologies, Hothead Games, Inc., Vivint Solar, etc use PouchDB. | Some companies like Citi, Bank of America, UPS, etc use MS SQL Server. |
| 13. | PouchDB does not provide ACID transactions concepts. | MS SQL Server provides ACID transaction concepts. |
| 14. | PouchDB does not provide the concept of Referential Integrity. Hence, no Foreign Keys. | MS SQL Server provides the concept of Referential Integrity and have Foreign Keys. |
| 15. | PouchDB supports Map Reduce method. | MS SQL Server does not support Map Reduce method. |
| 16. | PouchDB does not provide access control rights. | MS SQL Server provides access control rights according to SQL-standard. |
| 16. | PouchDB supports Javascript programming language. | MS SQL Server supports C#, C++, Delphi, Go, Java, JavaScript (Node.js), PHP, Python, R, Ruby, Visual Basic programming languages. |
| 17. | PouchDB has schema-free data. | MS SQL Server has fixed data schema. |
| 18. | PouchDB does not support SQL. | MS SQL Server support SQL. |