MySQL™ labels itself "The World's Most Popular Open Source Database" - which is probably not an exaggeration. First released in 1995 at the start of the Internet boom, it quickly became the dominant web database thanks to its speed, compact size and comparative ease of use - and liberal licensing policy, being distributed from the start as open source (and later under the GPL license) and free for many purposes. MySQL's availability for up-and-coming web-server platforms such as Linux as well as ports for desktop systems such as Windows, at a time when the major players in the database industry were still concentrating on "big iron" datacenter hardware played an important role as well.
Currently MySQL is typically found on web servers as a backend for web applications such as bulletin boards, user tracking and content management systems. One of its most high-profile web applications is as the backend for the very popular Wikipedia wiki-based encyclopedia.
Despite its "free software" epithet MySQL is very much a commercial product, and some forms of usage may require purchase of a non-GPL licence (refer to the website for more details). With a cash injection of around US$ 20,000,000 in June 2003 MySQL AB, the Swedish developer company, seems to be steering towards the lucrative "enterprise" market. The 2003 "acquisition" of the high-end open-source database SAP-DB may be a first step in this direction.
In October 2005 MySQL released version 5 of its flagship RDBMS product, providing features such as views and SQL functions, which have long been standard in other relational databases.
In the same month, InnoDB, which provides the only viable MySQL database engine with transactional support, was purchased by Oracle. While relations between MySQL AB and Oracle appear to remain cordial, the purchase has been followed by speculations as to Oracle's intentions. The plot thickened further in February 2006 when Oracle purchased SleepyCat Software, the creators of Berkeley DB, the only other MySQL storage engine besides from InnoDB with transactional capability.
MySQL is a trademark of MySQL AB.