MySQL developers have used Microsoft source code in version 4.1 of the open-source database, which is due for final release in late October.
Microsoft made the code for its Windows Installer XML (WiX) toolset available under an open-source licence in April 2004. The toolset is used by companies that develop applications for the Windows environment to build a Windows installation package.
David Axmark, co-founder of MySQL, said on Monday that the code has been used by MySQL developers to generate binary install files for the Windows environment. The code is not used for the MySQL database itself, but for the administration tool which connects to the database.
As Microsoft is known for zealously protecting the source code of its applications, some open-source developers were suspicious when they heard it was releasing the source code of WiX. But Axmark said MySQL had little hesitation about using it.
"If Microsoft releases something under public licence we will use it," he said.
However, he said that the code is only part of the build process rather than key application functionality.
"It's not that useful," said Axmark. "We may need to modify the code slightly so it has some value. But it doesn't have as much value as something you would put into an application."
Simon Riggs, a developer on PostgreSQL, an alternative open-source database, said that future versions of PostgreSQL will not include the Microsoft source code as the database already has a Microsoft installer which works fine.
Riggs pointed out that the WiX toolset is already programmable so there is little need to customise it.
"Microsoft open-sourcing this is like taking the top off a jar that is already open," said Riggs. "We're not interested in this bit of their source code."
A Microsoft spokeswoman said on Monday that Microsoft is committed to providing tools to aid software development. "WiX is just one example of our engagement with the open-source community and it helps software developers as they build software that runs on Windows," said the spokeswoman.