IBM DB2
IBM DB2 is a family of database server products developed by IBM. These products all support the relational model, but in recent years some products have been extended to support object-relational features and non-relational structures like JSON and XML.
Historically and unlike other database vendors, IBM produced a platform-specific DB2 product for each of its major operating systems. However, in the 1990s IBM changed track and produced a DB2 "common server" product, designed with a common code base to run on different platforms.
Current editions
Today, there are three main products in the DB2 family: DB2 for Linux, UNIX and Windows (informally known as DB2 LUW), DB2 for z/OS (mainframe), and DB2 for i (formerly OS/400).
A fourth product, DB2 for VM / VSE is also available.
History
DB2 traces its roots back to the beginning of the 1970s when Edgar F. Codd, a researcher working for IBM, described the theory of relational databases and in June 1970 published the model for data manipulation.