1. 微软 SQL 服务器：
Microsoft SQL Server 是一个关系数据库管理系统 (RDBMS)，它依赖于平台，并且是基于 GUI 和命令的软件。它支持企业 IT 环境中的各种事务处理、商业智能和分析应用程序。它由微软公司开发，最初于 1989 年 4 月 24 日发布。它是用 C 和 C++ 语言编写的。
2. MongoDB：
MongoDB 是一个跨平台的面向文档的非关系型(即 NoSQL)数据库程序。它是一个开源文档数据库，以键值对的形式存储数据。 MongoDB 由 MongoDB Inc. 开发，最初于 2009 年 2 月 11 日发布。它使用 C++、Go、JavaScript、 Python语言编写。 MongoDB 提供高速、高可用性和高可扩展性。
MS SQL Server 和 MongoDB 的区别：
| S.NO. | MS SQL server | Mongodb |
|---|---|---|
| 1. | Developed by Microsoft Corporation and initially released on April 24, 1989. | Developed by MongoDB Inc. and initially released on 11 February 2009. |
| 2. | MS SQL server is written in C and C++. | MongoDB is written in C++, Go, JavaScript, Python languages. |
| 3. | The primary database model for MS SQL Server is Relational DBMS | The primary database model for MongoDB is Document store. |
| 4. | The license for MS SQL Server is Commercial. | The license for MongoDB is Open Sourse. |
| 5. | MS SQL Server supports XML data format. | MongoDB does not supports XML data format. |
| 6. | MS SQL Server provides ACID transactions without snapshot isolation. | MongoDB provides Multi-document ACID transactions with snapshot isolation. |
| 7. | In MS SQL Server the data schema is Fixed. | In MongoDB the data schema is Dynamic. |
| 8. | MS SQL Server provides the concept of Referential Integrity and have Foreign keys. | MongoDB does not provides the concept of Referential Integrity. Hence no Foreign Keys. |
| 9. | MS SQL Server does not supports Map Reduce method. | MongoDB supports Map Reduce method. |
| 10. | Server operating systems for MS SQL Server are Linux Windows. | Server operating systems for MongoDB are Solaris, Linux, OS X, Windows. |
| 11. | Famous companies like Citi, Bank of America, UPS, etc uses MS SQL Server. | Famous companies like Adobe, Amadeus, Lyft, ViaVarejo, Craftbase, etc uses MongoDB. |