1. MySQL：
MySQL 是一种基于结构化查询语言 (SQL) 的开源关系数据库管理系统 (RDBMS)。它由oracle 公司开发和管理，于1995 年5 月23 日首次发布。它被广泛应用于许多小型和大型工业应用中，能够处理大量数据。
2.IBM Db2：
IBM Db2 是由 IBM 开发的一系列数据管理产品，包括数据库服务器。它是一个关系数据库管理系统 (RDBMS)，支持面向对象的特性和非关系结构的 XML。 Db2 旨在高效地存储、分析和检索数据。它最初于 1983 年发布，使用 C、C++、 Java和汇编语言编写。
MySQL 和 IBM Db2 之间的区别：
| SR.NO | MySQL | IBM Db2 |
|---|---|---|
| 1. | It was developed by Oracle. | It was developed by IBM. |
| 2. | It was released in May 1995. | It was released in 1983. |
| 3. | The primary database model for MySQL is Relational DBMS. | The primary database model for Db2 is also Relational DBMS. |
| 4. | Server operating systems for MySQL are FreeBSD, Linux, OS X, Solaris and Windows. | Server operating systems for Db2 are AIX, HP-UX, Linux, Solaris, Windows and z/OS. |
| 5. | It has the concept of Referential Integrity and Foreign keys. | It also has the concept of Referential Integrity and Foreign keys. |
| 6. | It is written in C and C++ languages. | It is written in C, C++, Assembly language, Java languages. |
| 7. | Some companies like Airbnb, Pinterest, Slack, Udemy, Twitter, etc use MySQL. | Some companies like JPMorgan Chase, Bank of America, Scotiabank, Citi, etc use Db2. |
| 8. | It has fixed data schema. | It also has fixed data schema. |