Relational databases: not just a pretty postcode

IBM's relational database, first announced for MVS mainframe environments. Since then, IBM has steadily extended it to all its platforms - including the AS/400 - and to most of its rivals' platforms as well.

When the fuss over object relational database erupted around 1997-98, IBM added extended data and multimedia capabilities and tried to repackage the product as DB2 Universal Database, or UDB.

In March 1999, Dataquest announced that DB2 had overtaken Oracle and maintained its lead over Microsoft to give it the biggest market share of any RDBMS in terms of licences sold.

Where did it originate?

Out of the work done by Codd and Date at IBM's San Jose labs. In 1981, IBM released its first SQL database - SQL/DS.

This was followed in 1983 by DB2, which was essentially a version of SQL/DS rewritten for MVS. However, Oracle pipped IBM to market with the first RDBMS, released in 1979.

What's it for?

You name it: OLTP and business intelligence applications, data warehousing and data mining, distributed e-business and mobile computing, multi-media management. IBM says existing applications can be extended to the Web with version 6.1.

What makes it special?

Its stability and reliability derived from its origin on the mainframe. Versions for smaller platforms are cut down versions of the data centre product, not jumped-up desktop filing systems like Microsoft's Access. The versions on different platforms are functionally identical, and applications can be ported from one to another.

IBM has surrounded DB2 with middleware products, offering gateways to most other databases and making it possible to build consolidated and "federated" databases on and around DB2.

How difficult is it to master?

It depends what you want to do. Like SQL, DB2 was originally intended as an end-user tool, but it soon became clear that users couldn't be expected to get their heads round relational concepts.

To become a DB2 Certified Solutions Expert, you will need an advanced programming course and a couple of years' real-world experience behind you.

Where is it used?

IBM has striven to make it universally available, to small- and medium-sized businesses, departments and large enterprises, from single users with laptops or desktop PCs to the largest clustered and massively parallel processor (MPP) servers.

Not to be confused with

A Derbyshire postcode, drum and bass, an Aston Martin.

What systems does it run on?

Windows NT, AIX, Linux, Sun's Solaris, Windows 95/98 (personal edition only), OS/2, Unixware 7, HP-UX, NUMA-Q, OS/390, VSE and VM, AS/400 and now Windows CE, EPOC and Palm Pilot hand-held devices.

Not many people know that . . .

a) Latest research shows that Web site visitors will move on if a hypertext link takes longer than eight seconds.

b) IBM expects you to wait from four to six weeks for delivery of its DB2 evaluation CD.

What's coming up?

DB2 version 6.1 now comes bundled with VisualAge for Java, Net.Data and the Websphere Application Server.

Training

You can download an evaluation copy of DB2 Personal Developers Edition for Windows NT, 95 and 98, OS/2 and Linux. There's also a complete range of self-study offerings, including preparation for DB2 certification. Other possibilities include IBM Redbook "How toÉ" guides. IBM has also begun to put its technical conference material online. There's a DB2 magazine, and a user group, which you can visit at www.idug.org. There are also sources of independent training and self-study courseware. Try for example www.venus.co.uk/dpec.

Rates of pay

The bulk of DB2 jobs on offer are still with CICS and Cobol, rather than Java and Net.thisandthat technologies. Y2K provided a boom market for these skills, and many people started contracting. It's too early to say whether their return to permanent work will depress salaries. Mainframe skills remain in demand. One recent ad promised DB2 training to anyone with two years' CICS, Cobol and DL/1, on a salary of £28K. DB2 database administrators are particularly in demand, with salaries of 45-50k on offer.