what is DB2

A {relational database} from {IBM}. When running under IBM's MVS ({Multiple Virtual Storage}) {operating system}, DB2 is implemented on top of {VSAM} and uses its underlying data structures. DB2, later called "DB2 Universal DataBase", also runs under {windows NT}, {AIX}, {Solaris} and, most recently, {Linux}

DB2 is a family of relational database management system (RDBMS) products from IBM that serve a number of different operating system platforms. According to IBM, DB2 leads in terms of database market share and performance. Although DB2 products are offered for Unix-based systems and personal computer operating systems, DB2 trails Oracle's database products in UNIX-based systems and Microsoft's Access in Windows systems.

In addition to its offerings for the mainframe OS/390 and VM operating systems and its mid-range AS/400 systems, IBM offers DB2 products for a cross-platform spectrum that includes UNIX-based Linux, HP-UX, Sun Solaris, and SCO UnixWare; and for its personal computer OS/2 operating system as well as for Microsoft's Windows 2000 and earlier systems. DB2 databases can be accessed from any application program by using Microsoft's Open Database Connectivity (ODBC) interface, the Java Database Connectivity (JDBC) interface, or a CORBA interface broker.


On January 30th, 2006, IBM released a no-charge edition of DB2 called DB2 9 Express-C. This was an expected response to the recently announced free versions of Oracle 10g and Microsoft SQL Server. Express-C will have no limit on number of users or database size. It is deployable on Windows and Linux machines with up to two processors (4 cores in total) and up to 4GB of memory.

DB2 can be administered from either the command-line or a GUI. The command-line interface requires more knowledge of the product but can be more easily scripted and automated. The GUI is a multi-platform Java client that contains a variety of wizards suitable for novice users. DB2 supports both SQL and XQuery. DB2 has native implementation of XML data storage, where XML data is stored as XML(not as relational data or CLOB data) for faster access using XQuery.