One of the most--if not the most--common backend database servers used in Web applications, MySQL is an open source offering free for both individual use, and, if necessary, modification. The source code is released under the GPL license and allows developers/implementors to use or modify the server on their own platforms and in their own or otherwise obtained applications that require an SQL-based backend. Further, MySQL can be included with applications that themselves are also distributed with a GPL license. A commercial license is available for those who cannot or do not wish to adhere to GPL terms; and is required for developers who wish to include MySQL in a commercially (i.e., non-GPL) distributed application.

Probably because of its Open Source roots, MySQL is often used in tandem with the Open Source language platforms PHP and Perl; and indeed third party tools and libraries integrating MySQL in these and other commonly used languages on the Web are easy to find as well as being typically free for downloading. The product itself (MySQL) is available to implement as both a standard client/server platform and as a library that can be embedded directly within an application (bearing in mind that distributed non-GPL applications including MySQL require a license purchase).

MySQL features an architecture that allows it to separate core database access from table handling functions; allowing users to implement the server with traditional transaction support or as a "transactionless" platform for improved performance. Separate, or no "table handlers" are provided depending on the version of MySQL chosen (see the MySQL Web site for current details).

Improvements in the latest release of of MySQL (beta v4, as of this writing) include:

- support for secure (SSL) traffic between the mysql deamon and the calling application

- support for the UNION statement

- FULLTEXT search properties and indexing enhancements

- the ability to set startup options without first bringing down the server

MySQL is available now from the MySQL Web site.