1 General Information about MySQL
This is the MySQL reference manual; it documents MySQL version 3.23.21-beta. As MySQL is work in progress, the manual gets updated frequently. So there is a very good chance that this version is out of date, unless you are looking at it on-line. The most recent version of this manual is available at
http://www.mysql.com/documentation / in many different formats. If you have a hard time finding the information in the manual, you can try its searchable PHP version at
http://www.mysql.com/documentation/manual.php .
MySQL is a very fast, multi-threaded, multi-user and robust SQL (Structured Query Language) database server.
The MySQL is free software. It is licensed with the GNU GENERAL PUBLIC LICENSE
http://www.gnu.org /. See section 3 MySQL licensing and support.
The MySQL home page provides the latest information about MySQL.
The following list describes some useful sections of the manual:
For a discussion of MySQL's capabilities, see section 1.5 The main features of MySQL.
For installation instructions, see section 4 Installing MySQL. For tips on porting MySQL to new machines or operating systems, see section H Comments on porting to other systems.
For information about upgrading from a 3.21 release, see section 4.16.2 Upgrading from a 3.21 version to 3.22.
For a tutorial introduction to MySQL, see section 9 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 bug fixes, see section E MySQL change history.
For a list of currently known bugs and misfeatures, see section F Known errors and design deficiencies in MySQL.
For future plans, see section G List of things we want to add to MySQL in the future (The TODO).
For a list of all the contributors to this project, see section D Contributors to MySQL.
IMPORTANT:
Reports of errors (often called bugs), as well as questions and comments should be sent to the mailing list at mysql@lists.mysql.com. See section 2.3 How to report bugs or problems. The mysqlbug script should be used to generate bug reports. For source distributions, the mysqlbug script can be found in the `scripts' directory. For binary distributions, mysqlbug can be found in the `bin' directory.
If you have any suggestions concerning additions or corrections to this manual, please send them to the manual team at (docs@mysql.com).
1.1 What is MySQL
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. Since computers are very good at handling large amounts of data, database management plays a central role in computing, as stand-alone 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 tables are linked by defined relations making it possible to combine data from several tables on request. The SQL part of MySQL stands for "Structured Query Language" - the most common standardized language used to access databases.
MySQL is Open Source Software
Open source means that itŽs possible to use and modify for anyone. Anybody can download MySQL from the Internet and use it without paying anything. Anybody so inclined can study the source code and change it to fit their needs. MySQL uses the GPL (GNU General Public License)
http://www.gnu.org , 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 into a commercial application you can buy a commercially licensed version from us.
Why use MySQL?
MySQL is very fast, reliable and easy to use. If thatŽs what YouŽre looking for you should give it a try. MySQL also has a very practical set of features developed in very close cooperation with our users. You can find a performance comparison of MySQL to some other database managers on our benchmark page. See section 12.7 Using your own benchmarks. MySQL was originally developed to handle very large databases much faster than existing solutions and has been successfully used in highly demanding production environments for several years. Though under constant development, MySQL today offers a rich and very useful set of functions. The connectivity, speed and security makes MySQL highly suited for accessing databases on the Internet.
The technical features of MySQL
For advanced technical information, section 7 MySQL language reference. MySQL is a client/server system that consists of an multi-threaded SQL server that supports different backends, several different client programs and libraries, administrative tools and a programming interface.
MySQL has a lot of contributed software available.
This makes it much more likely that you will find that your favorite application/language already supports MySQL.
The official way to pronounce MySQL is ``My Ess Que Ell'' (not MY-SEQUEL). But we try to avoid correcting people who say MY-SEQUEL
MySQL core values
We want MySQL to be
The best and the most used database in the world
Available to all and affordable for all
Easy to use
Continuously improved while remaining fast and safe
Fun to use and fun to improve
Free from bugs
MySQL AB and the people of MySQL AB
Promote Open Source Philosophy and support the Open Source Community
Aims to be good citizens
Prefer partners that share our values and mind-set
Answer mail and give support
Is a virtual company networking with others
Work against software patents
1.2 About this manual
This manual is currently available in Texinfo, plain text, Info, HTML, PostScript and PDF versions. Because of their size, PostScript and PDF versions are not included with the main MySQL distribution, but are available for separate download at
http://www.mysql.com /.
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.
This manual is written and maintained by David Axmark, Michael (Monty) Widenius and Paul DuBois. For other contributors, see section D Contributors to MySQL.
1.2.1 Conventions used in this manual
This manual uses certain typographical conventions:
constant
Constant-width font is used for command names and options; SQL statements; database, table and column names; C and Perl code; and environment variables. Example: ``To see how mysqladmin works, invoke it with the --help option.''
`filename'
Constant-width font with surrounding quotes is used for filenames and pathnames. Example: ``The distribution is installed under the `/usr/local/' directory.''
`c'
Constant-width font with surrounding quotes is also used to indicate character sequences. Example: ``To specify a wildcard, use the `%' character.''
italic
Italic font is used for emphasis, like this.
boldface
Boldface font is used for access privilege names (e.g., ``do not grant the process privilege lightly'') and occasionally to convey especially strong emphasis.
When commands are shown that are meant to be executed by a particular program, the program is indicated by the prompt shown with the command. For example, shell> indicates a co
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