1.卡桑德拉(Cassandra)：
Cassandra是一个免费的开放源代码的分布式宽列存储NoSQL数据库管理系统。它由Apache Software Foundation开发，最初于2008年7月发布。Cassandra旨在处理许多商用服务器上的大量数据，提供高可用性而没有单点故障。
2. MongoDB：
MongoDB是一个跨平台的面向文档的非关系(即NoSQL)数据库程序。它是一个开放源代码文档数据库，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，高可用性和高可伸缩性。
Cassandra和MongoBD之间的区别：
| S.NO. | Cassandra | MongoDB |
|---|---|---|
| 1. | Developed by Apache Software foundation and released on July 2008. | Developed by MongoDB Inc. and initially released on 11 February 2009. |
| 2. | Cassandra is written only in Java language. | MongoDB is written in C++, Go, JavaScript, Python languages. |
| 3. | Writing scalability in Cassandra is very high and efficient. | Writing scalability is limited in MongoDB |
| 4. | Read performance is highly efficient in Cassandra as it takes O(1) time. | Read performance is not that fast in MongoDB when compared to Cassandra. |
| 5. | Cassandra has only cursory support for secondary indexes i.e secondary indexing is resticted. | MongoDB does supports the concept of secondary indexes. |
| 6. | Cassandra only supports JSON data format. | MongoDB supports both JSON and BSON data formats. |
| 7. | The replication method that Cassandra supports is Selectable Replication Factor. | The replication method that MongoDB supports is Master Slave Replication |
| 8. | Cassandra does not provides ACID transactions but can be tuned to support ACID properties. | MongoDB provides Multi-document ACID transactions with snapshot isolation. |
| 9. | Server operating systems for Cassandra are BSD, Linux, OS X, Windows. | Server operating systems for MongoDB are Solaris, Linux, OS X, Windows. |
| 10. | Famous companies like Hulu, Instagram, Intuit, Netflix, Reddit, etc uses Cassandra. | Famous companies like Adobe, Amadeus, Lyft, ViaVarejo, Craftbase, etc uses MongoDB. |