MySQL is one of the supported databases that underpins a Moodle installation.
- If you are running Linux your preference should be to install using your distributions package manager. This ensures you will get any available updates.
- There are installers available for most popular operating systems at http://www.mysql.com/downloads/mysql/.
- It is possible and reasonably straightforward to build mysql from source but it is not recommended (the pre-built binaries are supposedly better optimised).
- Make sure you set a password for the 'root' user (see http://dev.mysql.com/doc/refman/5.0/en/default-privileges.html).
Consider installing and configuring my.cnf (the MySQL settings file) to suit your needs. The default configuration is usually very conservative in respect of memory usage versus performance.
- Increase the 'max_allowed_packet' setting to at least 4 megabytes.
- Make sure InnoDB storage engine is available, legacy MyISAM engine is not supported any more.
- Set 'innodb_file_per_table=1' and 'innodb_file_format=Barracuda' in [mysqld] section - these settings are required for compression of large database records.
Creating Moodle database
These are the steps to create an empty Moodle database. Substitute your own database name, user name and password as appropriate.
The instructions assume that the web server and MySQL server are on the same machine. In this case the 'dbhost' is 'localhost'. If they are on different machines substitute the name of the web server for 'localhost' in the following instructions and the 'dbhost' setting will be the name of the database server.
- To create a database using the 'mysql' command line client, first log into MySQL
$ mysql -u root -p Enter password:
(Enter the password you previously set - or been given - for the MySQL 'root' user). After some pre-amble this should take you to the mysql> prompt.
- Create a new database (called 'moodle' - substitute your own name if required). We recommend you use utf8_unicode_ci for collation.
mysql> CREATE DATABASE moodle DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci;
- Add a user/password with the minimum needed permissions:
mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,CREATE TEMPORARY TABLES,DROP,INDEX,ALTER ON moodle.* TO moodleuser@localhost IDENTIFIED BY 'yourpassword';
...which creates a user called 'moodleuser' with a password 'yourpassword'. Make sure you invent a strong password and resist the temptation to 'GRANT ALL'.
phpMyAdmin is a web based administration tool for MySQL. If this is available you can use it to create a new database. Make sure that you select 'UTF8' as the default character set.
Which database belongs to which Moodle
If you have installed several Moodle installations on the same server, there will be several several databases in your MySQL server. The names might be quite poor reflections of the content like _mdl1 _mdl2 _mdl3 . So how do I see which database goes with which Moodle installation? You can go in with phpMyAdmin and in the various databases check for the table "mdl_course". There you will easily see the name of that Moodle Installation. In table mdl_config you can see the Moodle version. (Where can one find the home relative URL of the Moodle installation?)