Datos ii usil

The IBM DB2 Enterprise Server Edition is a relational model database server developed by IBM. It primarily runs on Unix (namely AIX), Linux, system i (formerly as/400), z/OS and Windows servers. DB2 also powers the different IBM InfoSphere Warehouse editions. Alongside DB2 is another RDBMS: Informix, which was acquired by IBM in 2001.
History
DB2 has a long history and is considered by many tohave been the first database product to use SQL (also developed by IBM) although Oracle released a commercial SQL database product somewhat earlier than IBM did.
The name DB2 was first given to the Database Management System or DBMS in 1983 when IBM released DB2 on its MVS mainframe platform. Prior to this, a similar product was named SQL/DS on the VM platform. The earlier System 38 platformalso contained a relational DBMS. System Relational, or System R, was a research prototype developed in the 1970s. DB2 has its roots back to the beginning of the seventies when E.F. Codd, working for IBM, described the theory of relational databases and in June 1970 published the model for data manipulation. To apply the model Codd needed a relational database language which he named Alpha. At thetime IBM didn't believe in the potential of Codd's ideas, leaving the implementation to a group of programmers not under Codd's supervision, who violated several fundamentals of Codd's relational model; the result was Structured English QUEry Language or SEQUEL. When IBM released its first relational database product, they wanted to have a commercial-quality sublanguage as well, so it overhauledSEQUEL and renamed the basically new language(System Query Language) SQL to differentiate it from SEQUEL.
Historically, when Informix acquired Illustra and made their database engine an object-SQL DBMS by introducing their Universal Server, both Oracle and IBM followed suit by changing their database engines to be capable of object-relational extensions. Moreover, in 2001, IBM bought Informixand in the following years incorporated Informix technology into the DB2 product suite. Today, DB2 can technically be considered to be an object-SQL DBMS.
For some years DB2, as a full-function DBMS, was exclusively available on IBM mainframes. Later IBM brought DB2 to other platforms, including OS/2, UNIX and Windows servers, then Linux (including Linux on zSeries) and PDAs. This process wasmainly undertaken through the 1990s. The inspiration for the mainframe version of DB2's architecture came in part from IBM DL/I and IBM IMS, both initially hierarchical and then later network (or CODASYL) databases. DB2 is also embedded in the i5/OS operating system for IBM System i (iSeries, formerly the AS/400), and versions are available for z/VSE and z/VM.
An earlier version of the code thatwould become DB2 LUW (Linux, Unix, Windows) was part of an Extended Edition component of OS/2 called Database Manager. IBM extended the functionality of Database Manager a number of times, including the addition of distributed database functionality that allowed shared access to a database in a remote location on a LAN. Eventually IBM declared that insurmountable complexity existed in the DatabaseManager code, and took the difficult decision to completely rewrite the software in their Toronto Lab. The new version of Database Manager, called DB2 like its mainframe parent, ran on the OS/2 and RS/6000 platforms, was called DB2/2 and DB2/6000 respectively. Other versions of DB2, with different code bases, followed the same '/' naming convention and became DB2/400 (for the AS/400), DB2/VSE (forthe DOS/VSE environment) and DB2/VM (for the VM operating system). IBM lawyers stopped this handy naming convention from being used and decided that all products needed to be called "product FOR platform" (for example, DB2 for OS/390). The next iteration of the mainframe and the server-based products were named DB2 Universal Database (or DB2 UDB), a name that had already been used for the...