MySQL is a multi-threaded, multi-threaded database management system with more than six million installations . MySQL AB develops MySQL as free software in a dual licensing scheme. On the one hand it offers it under the GNU GPL, but, companies that want to incorporate it into private products can buy from the company a license that allows that use.
It is developed for the most part in ANSI C.
Unlike projects like Apache, where software is developed by a public community, and the copyright of the code is held by the individual author, MySQL is owned and sponsored by a private company, which owns the copyright of most of the code . This is what makes possible the above mentioned licensing scheme. In addition to the sale of private licenses, the company offers support and services. For their operations they hire workers around the world who collaborate via Internet. MySQL AB was founded by David Axmark, Allan Larsson, and Michael Widenius.