This is the Reference Manual for the MySQL Database System, version 5.1, through release 5.1.7-beta. It is not intended for use with older versions of the MySQL software due to the many functional and other differences between MySQL 5.1 and previous versions. If you are using an earlier release of the MySQL software, please refer to the MySQL 5.0 Reference Manual, which covers the 5.0 series of MySQL software releases, or to MySQL 3.23, 4.0, 4.1 Reference Manual, which covers the 3.23, 4.0, and 4.1 series of MySQL software releases. Differences between minor versions of MySQL 5.1 are noted in the present text with reference to release numbers (5.1.x).

Because this manual serves as a reference, it does not provide general instruction on SQL or relational database concepts. It also does not teach you how to use your operating system or command-line interpreter.

The MySQL Database Software is under constant development, and the Reference Manual is updated frequently as well. The most recent version of the manual is available online in searchable form at https://dev.mysql.com/doc/. Other formats also are available there, including HTML, PDF, and Windows CHM versions.

The Reference Manual source files are written in DocBook XML format. The HTML version and other formats are produced automatically, primarily using the DocBook XSL stylesheets. For information about DocBook, see https://docbook.org/

If you have any suggestions concerning additions or corrections to this manual, please send them to the documentation team at <[email protected]>.

This manual was originally written by David Axmark and Michael “Monty” Widenius. It is maintained by the MySQL Documentation Team, consisting of Paul DuBois, Stefan Hinz, Mike Hillyer, and Jon Stephens. For the many other contributors, see Appendix C, Credits.

The copyright to this manual is owned by the Swedish company MySQL AB. MySQL® and the MySQL logo are registered trademarks of MySQL AB. Other trademarks and registered trademarks referred to in this manual are the property of their respective owners, and are used for identification purposes only.