The MySQL (R) software delivers a very fast, multi-threaded, multi-user, and robust SQL (Structured Query Language) database server. MySQL Server is intended for mission-critical, heavy-load production systems as well as for embedding into mass-deployed software. MySQL is a registered trademark of MySQL AB.

The MySQL software is Dual Licensed. Users can choose to use the MySQL software as an Open Source product under the terms of the GNU General Public License (http://www.fsf.org/licenses/) or can purchase a standard commercial license from MySQL AB. See http://www.mysql.com/company/legal/licensing/ for more information on our licensing policies.

The following list describes some sections of particular interest in this manual:

• For a discussion about the capabilities of the MySQL Database Server, see section The Main Features of MySQL.
• For installation instructions, see section Installing MySQL.
• For tips on porting the MySQL Database Software to new architectures or operating systems, see section Porting to Other Systems.
• For information about upgrading from a Version 4.0 release, see section Upgrading from Version 4.0 to 4.1.
• For information about upgrading from a Version 3.23 release, see section Upgrading from Version 3.23 to 4.0.
• For information about upgrading from a Version 3.22 release, see section Upgrading from Version 3.22 to 3.23.
• For a tutorial introduction to the MySQL Database Server, see section MySQL Tutorial.
• For examples of SQL and benchmarking information, see the benchmarking directory (`sql-bench' in the distribution).
• For a history of new features and bugfixes, see section MySQL Change History.
• For a list of currently known bugs and misfeatures, see section Known Errors and Design Deficiencies in MySQL.
• For future plans, see section MySQL and the Future (the TODO).
• For a list of all the contributors to this project, see section Credits.

Important:

Reports of errors (often called ``bugs''), as well as questions and comments, should be sent to http://bugs.mysql.com. See section How to Report Bugs or Problems.

If you have found a sensitive security bug in MySQL Server, please let us know immediately by sending an email message to security@mysql.com.

In this chapter

About This Manual

This is the Reference Manual for the MySQL Database System. It documents MySQL up to Version 5.0.3-alpha, but is also applicable for older versions of the MySQL software (such as 3.23 or 4.0-production) because functional changes are indicated with reference to a version number.

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 http://dev.mysql.com/doc/. Other formats also are available, including HTML, PDF, and Windows CHM versions.

The primary document is the Texinfo file. The HTML version is produced automatically using a modified version of texi2html. The plain text and Info versions are produced with makeinfo. The PostScript version is produced using texi2dvi and dvips. The PDF version is produced with pdftex.

If you have any suggestions concerning additions or corrections to this manual, please send them to the documentation team at docs@mysql.com.

This manual was initially written by David Axmark and Michael ``Monty'' Widenius. It is maintained by the MySQL Documentation Team, consisting of Paul DuBois, Stefan Hinz, Mike Hillyer, Jon Stephens, and Russell Dyer. For the many other contributors, see section Credits.

The copyright (2004) 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.

Overview of the MySQL Database Management System

MySQL, the most popular Open Source SQL database management system, is developed, distributed, and supported by MySQL AB. MySQL AB is a commercial company, founded by the MySQL developers. It is a second generation Open Source company that unites Open Source values and methodology with a successful business model.

The MySQL Web site (http://www.mysql.com/) provides the latest information about MySQL software and MySQL AB.

MySQL is a database management system.

A database is a structured collection of data. It may be anything from a simple shopping list to a picture gallery or the vast amounts of information in a corporate network. To add, access, and process data stored in a computer database, you need a database management system such as MySQL Server. Since computers are very good at handling large amounts of data, database management systems play a central role in computing, as standalone utilities or as parts of other applications.

MySQL is a relational database management system.

A relational database stores data in separate tables rather than putting all the data in one big storeroom. This adds speed and flexibility. The SQL part of ``MySQL'' stands for ``Structured Query Language.'' SQL is the most common standardized language used to access databases and is defined by the ANSI/ISO SQL Standard. The SQL standard has been evolving since 1986 and several versions exist. In this manual, ``SQL-92'' refers to the standard released in 1992, ``SQL:1999'' refers to the standard released in 1999, and ``SQL:2003'' refers to the current version of the standard. We use the phrase ``the SQL standard'' to mean the current version of the SQL Standard at any time.

MySQL software is Open Source.

Open Source means that it is possible for anyone to use and modify the software. Anybody can download the MySQL software from the Internet 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), http://www.fsf.org/licenses/, to define what you may and may not do with the software in different situations. If you feel uncomfortable with the GPL or need to embed MySQL code into a commercial application, you can buy a commercially licensed version from us. See the MySQL Licensing Overview for more information (http://www.mysql.com/company/legal/licensing/).

The MySQL Database Server is very fast, reliable, and easy to use.

If that is what you are looking for, you should give it a try. MySQL Server also has a practical set of features developed in close cooperation with our users. You can find a performance comparison of MySQL Server with other database managers on our benchmark page. See section The MySQL Benchmark Suite. MySQL Server was originally developed to handle large databases much faster than existing solutions and has been successfully used in highly demanding production environments for several years. Although under constant development, MySQL Server today offers a rich and useful set of functions. Its connectivity, speed, and security make MySQL Server highly suited for accessing databases on the Internet.

MySQL Server works in client/server or embedded systems.

The MySQL Database Software is a client/server system that consists of a multi-threaded SQL server that supports different backends, several different client programs and libraries, administrative tools, and a wide range of application programming interfaces (APIs). We also provide MySQL Server as an embedded multi-threaded library that you can link into your application to get a smaller, faster, easier-to-manage product.

A large amount of contributed MySQL software is available.

It is very likely that your favorite application or language supports the MySQL Database Server.

The official way to pronounce ``MySQL'' is ``My Ess Que Ell'' (not ``my sequel''), but we don't mind if you pronounce it as ``my sequel'' or in some other localized way.

MySQL Development Roadmap

This section provides a snapshot of the MySQL development roadmap, including major features implemented or planned for MySQL 4.0, 4.1, 5.0, and 5.1. The following sections provide information for each release series.

The current production release series is MySQL 4.1, which was declared stable for production use as of Version 4.1.7, released in October 2004. The previous production release series is MySQL 4.0, which was declared stable for production use as of Version 4.0.12, released in March 2003. Production status means that future 4.1 and 4.0 development is limited only to bugfixes. For the older MySQL 3.23 series, only critical bugfixes are made.

Active MySQL development currently is taking place in the MySQL 5.0 release se

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