1. IBM DB2：
IBM DB2 是一个数据库，它具有关系模型并以其性能而闻名。它具有很高的可扩展性，也以可靠性着称。它是一个商业软件，IBM DB2 的主要工作原理是 ACID。它是由 IBM 于 1983 年开发的。IBM DB2 中使用的分区方法是分片。它支持多种查询语言，如 SQL、JSON、XML、SPARQL 等。它是用 C 和 C++ 语言实现的。 IBM DB2 广泛用于存储大量数据和执行事务。
2. PostgreSQL :
PostgreSQL 是一种具有对象关系模型的数据库，由 PostgreSQL 全球开发组于 1989 年开发，是一款功能强大的免费开源软件。它也被称为 Postgres。 PostgreSQL 得到了大多数操作系统的支持，并且具有良好的性能。它是 SQL 的扩展版本并具有附加功能。它主要是根据ACID的原理工作的。它是用C语言实现的。
IBM DB2 和 PostgreSQL 的区别：
| S.NO. | IBM DB2 | PostgreSQL |
|---|---|---|
| 1. | IBM DB2 is a relational database model. | PostgreSQL is a object-relational database model. |
| 2. | IBM DB2 was developed by IBM in 1983. | PostgreSQL was developed by PostgreSQL Global Development group in 1989. |
| 3. | In IBM DB2 partitioning is done by sharding. | In IBM DB2 partitioning is done by use of list, hash and range. |
| 4. | It has a commercial license. | It is a open source software. |
| 5. | It is written in C and C++ languages. | It is written in C++ language. |
| 6. | It is a family of database management products given by IBM. | It is a advanced relational DBMS that is a extended form of SQL. |
| 7. | It has less availability as compared to PostgreSQL. | It has more availability as compared to IBM DB2. |
| 8. | In terms of ranking it is considered lower than PostgreSQL. | It is considered better than IBM DB2 in terms of ranking. |
| 9. | It has more scalability as compared to PostgreSQL. | It has less scalability as compared to IBM DB2. |
| 10. | It has query languages such as SQL, JSON, XML, XPATH, SPARQL. | It has SQL as its query language. |