The sales pitch for EnterpriseDB (EDB) is pretty simple: it's an enterprise-class relational database management system (RDBMS) based on twenty years of open-source development, compatible with Oracle - and costing a fraction of the price of a commercial system.

EDB is based on the BSD-licensed database PostgreSQL, widely considered the most advanced open-source DBMS around, with the addition of commercial features such as Oracle compatibility and enterprise-level support. If the business model sounds familiar, that's because it's the same idea with which Linux distributors and companies such as MySQL have already found success.

It was just a matter of time before PostgreSQL got the same treatment, say industry observers. Regardless of EDB's eventual success or failure, the staggering prices of commercial DBMS and the existence of high-quality open source databases mean the opportunity is there, analysts say. What's more, the open source licence used by products such as EDB means that if the company disappears, the code can still be developed and maintained, meaning less risk for customers.

The obvious question is: if PostgreSQL has been around so long - it was developed, along with Ingres, by Michael Stonebraker in the 1980s - why has it taken so long to get the backing of a commercial company? The answer, says EDB chief executive Andy Astor, is that enterprises have only recently begun to take an interest in open source as a database alternative. "Until the success of Linux in the enterprise, it was not possible to bring an enterprise-class open source database to market," he says. "Now, as CIOs are driving to cut costs while improving and expanding service, they are looking to open source to help them with these objectives."

The success of Linux, Apache, JBoss and Gluecode (acquired by IBM in May 2005) have all been signals to enterprise CIOs that open source can be a serious choice in the enterprise, Astor says. In the meantime, MySQL has grown into the most popular open-source database on the market, partly because of the multiple levels of support offered by MySQL AB, the Swedish company that owns and finances the project. However, MySQL has always lacked and even disparaged basic relational database features such as stored procedures, views and triggers. These and some other high-end features are to be belatedly added in MySQL 5.0, currently in beta release, but even so, the software is not taken seriously for uses more heavy-duty than Web applications.

PostgreSQL is another matter entirely. It was developed from the beginning to deal with the high-end database issues that had been encountered with the earlier Ingres project, and includes nearly all of the features expected from an enterprise-level database, including triggers, views and stored procedures in multiple languages.

Performance is another issue: MySQL is very fast for certain types of applications - typically Web applications - but doesn't scale, according to EDB. PostgreSQL, by contrast, is tuned for online transaction processing (OLTP), and EDB's extended version is further tuned to rival proprietary vendors' performance, the company claims.

What PostgreSQL has lacked until recently is the backing to turn it into a fully commercial, supported enterprise product. Growing enterprise interest in the database has been reflected in recent activity from some commercial companies, such as Pervasive Software, which launched a support package around PostgreSQL in January, along with a modified version called Pervasive Postgres. The development of PostgreSQL 8.0, also launched in January, was sponsored by commercial companies such as Fujitsu and Red Hat, who also offer support packages for the database. Companies such as IBM and Sun are trying to tap into the interest by developing their own open-source database offerings.

EDB has gone a step further by putting more development resources into the database, extensively modifying it, the company says. "EDB's core business is to deliver an enterprise-class database that is compatible with many Oracle applications, offered at an open source price point," Astor says. "We may provide support for PostgreSQL in the future, but that would only be as a service to our customers."

So far EDB's development efforts have focused on compatibility features. For example, the database's SQL syntax, data types, triggers and procedural language have been modified to be compatible with Oracle - the so-called "Redwood" compatibility mode - meaning that skills are transferable and many Oracle applications can work with EDB without modification.

A "Redmond" mode - compatibility with SQL Server - is on the way. The software has been designed so that it feels familiar to developers and administrators used to Oracle and SQL Server. At the same time, EDB claims to have the strongest support for the ANSI SQL standard of any mainstream commercial or open-source database.

The PostgreSQL project itself has tended to stick with the ANSI standard, shying away from Oracle compatibility where this conflicts with ANSI, in order to keep things simple for users. There's nothing wrong with this technically speaking, argues EDB's Astor, but enterprises want something they can drop into their entrenched Oracle and Microsoft systems. If switching to another database means retraining, it will never happen, he says.

The EDB database is currently available as a beta release, with the first commercial release to follow this summer; during the beta period, all users get free technical support. The company has about 45 employees, a quarter of whom are devoted to customer support, EDB says.

The product includes EDB Database Server, the main RDBMS engine; EDB Studio, a console for developers and administrators; and EDB Connectors, linking EDB to the JDBC, ODBC, .Net, ESQL/C++, PHP, Perl and Python programming environments.