Oracle intends to release a free version of its database, a reaction to the growing competitive pressure from low-end open-source databases.

The database heavyweight on Tuesday is expected to announce the beta release of Oracle 10g Express Edition (Oracle Database XE), which will be generally available by the end of the year. It is targeted at students, small organisations and software vendors that could embed the Oracle database with an application.

The latest edition is the same as other databases in Oracle's lineup but is limited in usage. It can only run servers with one processor, with 4GB of disk memory and 1GB of memory.

The new low-end edition is aimed squarely at free and open-source alternatives to Oracle's namesake database, said Andrew Mendelsohn, senior vice president of Oracle's server technologies division.

Open-source databases have caught on steadily in popularity over the past few years with corporate customers and Web developers.

MySQL is the most popular open-source database among developers, according to a recent Evans Data study. IBM earlier this month released a free version of its own DB2 database as part of a PHP development package. And Microsoft intends to ship a free version of SQL Server 2005, called Express, next month.

"There is definitely a market there (for low-end databases) and a demand. And we want them to be using Oracle and not MySQL or SQL Server Express," Mendelsohn said. "It's definitely a reaction to the market interest."

About a year and a half ago, Oracle introduced Oracle 10g Standard Edition One, a version aimed at mid-size companies where Microsoft has many customers. That database is limited to two processors and cost US$149 per user.

By introducing a free entry-level product, Oracle intends to get more developers and students familiar with its namesake database, Mendelsohn said. Those customers, Oracle hopes, will eventually upgrade to a higher-end version.

"Even though the database is initially free, standards progress and those university students who are playing with the database today will eventually be working at corporations and making product decisions," he said. "We want to have mind-share with those people."

The Express Edition database can be distributed with other products. It will be available through Oracle's developer network and include a Web-based administration console development tools.

Separately, Mendelsohn offered comments on what Oracle intends to do with InnoDB, a storage engine for the MySQL database that Oracle acquired earlier this month.

He said Oracle intends to extend a contract with MySQL where the InnoDB storage engine is packaged with MySQL.

"There are all kinds of possibilities we're exploring," Mendelsohn said. "You might be seeing it showing up in Oracle products."