License to share
Licensing, or how the source code is allowed to be modified and shared, can have a real impact on choosing an open-source database. The PostgreSQL license is modeled after the BSD license, which allows modifications of the code to be released into the open-source world at the author's discretion.
This open license is ideal for software vendors that want to use PostgreSQL as part of their solution. Since the PostgreSQL license does not force the derived solution to also become open source, the vendor can choose to open-source their code if or when it meets their business model.
MySQL is shared via GNU General Public License (GNU GPL) and controlled by Oracle. The GNU GPL is more liberal in its views of open-sourcing derived works in that it is in place to encourage the free sharing of code. This protects the original authors of the code by forcing new solutions based on the original project to take on the GNU GPL license as well.
While the comparisons of MySQL and PostgreSQL start with the fact that both are open-source relational databases, the similarities generally stop there. Each database has its own distinctive use cases, with only a small amount of overlap. In either case, they are high-quality databases that should be seriously considered over the more expensive proprietary databases-especially in light of today's tough economy.
Jim Mlodgenski is Chief Architect at EnterpriseDB. Jim is one of EnterpriseDB's first employees, having joined the company in May 2005. Over the years, Jim has been responsible for key activities such as sales engineering, professional services, strategic technology solutions delivery and customer education. Prior to joining EnterpriseDB, Jim was a partner and architect at Fusion Technologies, a technology services company. For nearly a decade, Jim developed early designs and concepts for Fusion's consulting projects, and specialized in Oracle application development, Web development and open-source information architectures. He can be reached at firstname.lastname@example.org.