What is it?
DB2 may hold more of the world's relational data than any other relational database system, but Oracle makes double the revenue, according to figures released in May by analyst firms Gartner and IDC.
But at a time when nominally free databases such as MySQL and PostgreSQL are claiming increasing share of the relational database management system market, revenue is a double-edged measure of success.
Like DB2, Oracle holds so many of the world's irreplaceable databases that even if new sales stopped tomorrow, people with sound Oracle skills and experience could reasonably expect never to be out of work.
But like other big proprietary suppliers, Oracle makes a lot of its revenue from training and certification, which presents the independent self-improver with a challenge.
Earlier this year, however, Oracle offered a new way to acquire skills for people without an employer's training budget to back them, when it joined the Express train by launching a free version, Oracle Database 10g Express Edition (XE).
Where did it originate?
Oracle was developed by Larry Ellison and two colleagues at a consultancy called Software Development Laboratories. It was named after a CIA-funded project they had worked on.
The company changed its name to Relational Software in 1979, when Oracle 2 was released, before completing the name transition to Oracle in 1983, when Oracle 3 was released, rewritten in the C language.
Oracle joined the move to client/server and in 1997 released the object-relational Oracle 8. XML read/write capability was added with Oracle 9i in 2001, and Oracle 10g appeared in 2003 (the "g" stands for "grid computing ready").
What's it for?
Applications are increasingly developed in Java, or Oracle Developer Tools for Visual Studio .net, rather than the proprietary PL/SQL using Oracle Forms and Oracle Reports.
Oracle claims that "hundreds of thousands of Java, .net, PHP and web programmers", including third-party application providers, have downloaded Oracle XE, which is built on the same code base as the full-price 10g release 2.
XE includes Oracle Application Express (Apex) release 2.1, which Oracle describes as "a declarative, graphical development environment for creating database-centric web applications".
Apex is effectively the front-end to XE, and most XE administration tasks are done using Apex's web-based interface, which is designed for users with little Oracle experience.
Oracle expects that users will upgrade to a paid-for version when they hit the limits of XE.
How difficult is it to master?
Not as hard as it used to be, as Oracle moves to a wizard-driven environment, and developers adopt industry-standard languages for their Oracle applications. But expensively trained and certified, highly skilled database administrators are still in demand.
What systems does it run on?
Paid-for 10g runs on IBM z/OS, IBM AIX, Sun Solaris, HP-UX, Linux, Microsoft Windows and Apple Mac. The Express Edition is available for Windows and Linux, but is restricted to a single CPU.
Oracle Database XE can be downloaded free from the Oracle Technology Network. There is also a free online forum for registered XE users, and free "Oracle by Example" tutorials.
Rates of pay
With a couple of years' experience, Oracle database administrators can earn £35,000 to £45,000, or £400-plus a day as contractors. Developers start at £20,000 to £30,000 depending on location and industry.
Vote for your IT greats
Who have been the most influential people in IT in the past 40 years? The greatest organisations? The best hardware and software technologies? As part of Computer Weekly’s 40th anniversary celebrations, we are asking our readers who and what has really made a difference?
Vote now at: www.computerweekly.com/ITgreats