MySQL, the popular open source SQL database management system, is developed, distributed, and supported by Oracle. "Open source" means that it is possible for anyone to use and modify the software. Anybody can download the MySQL software and use it without paying anything. If you wish, you may study the source code and change it to suit your needs. The MySQL software uses the GPL (GNU General Public License) to define what you may and may not do with the software in different situations.