Today the company that develops and controls the db4objects object database announced that in addition to the GNU General Public License and a commercial use license, it will also be offering its flagship product under a new, more freely distributable agreement: the db4objects Opensource Compatibility License (dOCL). This allows the software to be redistributed with a wider range of non-commercial open source projects, many of which cannot easily redistribute programs licensed under the GPL. An explanation of this software, the license, and a brief interview with db4objects CEO Christof Wittig are below.

Object databases

By far the most popular database frameworks in production today are relational database management systems (RDBMS). They were designed in and for an era when procedural programming was the only logical and widely-accepted method of solving problems with software. Data was a consequence of a program, not its basis. Today though, object-oriented programming is a more popular approach to solving problems because it is data-focused, and therefore can grow and evolve more easily, especially in environments where data or client needs are dynamic. Using yesterday's RDBMS software with today's object-oriented applications requires a lot of learning, frustration, and/or a glue layer between the two programs which significantly degrades application performance. That's where object databases come in; they're designed specifically for object-oriented programs, and make things easier and faster in many ways.

db4objects is the most popular and widely-used object database framework, with nearly a million deployments and more than 20,000 registered Java and .NET developers. You can download it for free and use it in any way you wish, but if you plan on selling it as part of a commercial product that you don't want to be at all open source, you can enter into a commercial distribution agreement with db4objects whereby you pay it between 3%-5% of the bill of materials price of your product.

Explaining the dOCL

The db4objects Opensource Compatibility License is designed to allow free redistribution for non-commercial use. Previously the company had a dual-license scheme by which the software was developed and distributed under the GNU General Public License and offered for free download, but was also sold under a commercial license that required payment for each program or product sold with db4objects embedded in it. This is still the current approach, but there is now a third option: the dOCL.

The GNU GPL accounts for a large percentage of open source software (and a larger percentage of free software, which has stricter terms than the open source definition), but is not backwards-compatible with GPL-incompatible free software or open source licenses. In other words, there are many projects under, for instance, the BSD or Apache licenses that can't distribute GPL-licensed software. The dOCL is the solution to the distribution problem presented by the GPL in such instances.

"Dual licensing is a well-understood model in the industry and is already used by companies like MySQL. It makes it easy to download, use, and evaluate db4objects," Christof Wittig, the db4objects CEO told me in an interview.

The terms of the dOCL are documented on the db4objects site, and are thus generally explained:

• In addition to the dOCL, db4objects is licensed under both a commercial, royalty-based license agreement, and the GNU General Public License v2.0. You may choose to license the software under any of the three agreements.
• You can create derivative works of db4objects, but if you do, you must license them under the GPL unless they were previously governed by one of the following licenses: LGPL versions 2.0 and 2.1; Apache Software License version 1.0, 1.1., or 2.0; BSD as published on July 22, 1999; Eclipse Public License version 1.0. If your program was previously published under the terms of one of those agreements before you incorporated db4objects into it, you can publish your derivative work under the same.
• You must register in the ProjectSpaces section of the db4o Developer Community.
• db4objects retains ownership of the software, including all patents and copyrights therein.
• You cannot delete or in any way alter the copyright, trademark, or other proprietary rights notices in db4objects.
• db4objects may publicize your use of the software for marketing purposes.

Many of the above terms and restrictions prevent the dOCL from being classified as a free software license. The licensing of derivative works clause also precludes db4objects from being considered open source by the official open source definition, which requires that derivative works be able to be licensed under the same terms as the original. Still, the license serves its purpose: to allow db4objects to be incorporated into non-GPL open source software projects under reasonably non-restrictive terms.

The best of both worlds?

"Open source software is not only a 'commoditizer' of well-understood product categories, but also a force to disrupt markets with new technologies by mitigating vendor lock-in from the Oracles and Microsofts of this world," Wittig said. "It's less disruptive for developers, though, because it's free to try it out and very easy to use. You can have this running in 10 minutes."

db4objects differs from many other dual-licensed software packages in that the open source edition is materially and functionally the same as the proprietary edition. Other companies -- like MySQL -- offer an improved commercial product and a reduced open source edition. Still others offer a totally free product, but complicate its interface in such a way that a support contract is necessary to install, customize, and maintain it. Wittig told me, "We believe charging for services on free products encourages the creation of difficult-to-use software. Our commercial license creates our revenue stream."

Heather Meeker of the Greenberg Traurig law firm and co-chair of the Open Source Software subcommittee of the Science and Technology Section of the American Bar Association analyzed this situation in depth in a 6-page whitepaper, released today as part of the db4objects official announcement. In it, Meeker provides an honest perspective on the market's need for dual licensing schemes, and how db4objects approached the situation while still honoring the GNU General Public License.

Discuss this article or get technical support on our forum.

Copyright 2007 JEM Electronic Media, Inc. No reprints without written permission.