1.德比：
Derby 是一个用Java实现的功能齐全的开源关系数据库管理系统 (RDBMS)，顾名思义，它是由 Apache Software Foundations 开发的。它基于Java、JDBC 和 SQL 标准。 Derby 易于安装、部署和使用。它要么嵌入到Java应用程序中，要么用作数据库服务器。
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。它是用 C++、Go、JavaScript、 Python语言编写的。 MongoDB 提供高速、高可用性和高可扩展性。
Derby 和 MongoDB 的区别：
| SR.NO | Derby | MongoDB |
|---|---|---|
| 1 | It is developed by Apache Software Foundation in 1997. | It is developed by MongoDB Inc. on 2009. |
| 2 | It is written in Java language. | It is written in C++ language. |
| 3 | The primary database model for Derby is Relational DBMS. | The primary database model for MongoDB is Document store. |
| 4 | Server operating systems for Derby are Windows, macOs, Linux, Unix, BSD and z/OS. | Server operating systems for MongoDB are Linux, OS X, Solaris and Windows. |
| 5 | It has Java Stored Procedures for Server-side scripts. | It has Javascript for Server-side scripts. |
| 6 | It support Master-Slave Replication methods. | It also support Master-Slave Replication methods. |
| 7 | APIs and other access methods used by Derby is JDBC. | APIs and other access methods used by MongoDB is proprietary protocol using JSON. |
| 8 | It support only Java programming language. | It support C, C#, C++, D, Delphi, Java, JavaScript, Lua, MatLab, Objective-C, Perl, PHP, PL/SQL, Python, R, Ruby, Scala, etc. |
| 9 | It provide XML support. | It do not provide XML support. |
| 10 | It support fine grained access rights according to SQL-standard. | It do not support access rights for user. |
| 11 | It does not support any Partitioning methods. | In MongoDB, partitioning can be done by Sharding. |
| 12 | It does not supports Map Reduce method. | It supports Map Reduce method. |
| 13 | It provides Immediate Consistency method to ensure consistency in a distributed system. | It provides both Eventual Consistency and Immediate Consistency methods to ensure consistency in a distributed system. |
| 14 | It provides multi-document ACID transactions with snapshot isolation | It provides ACID transactions. |