Convirtiendo su base de datos MySQL a UTF8

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This document describes how to convert your MySQL database from the latin1 charset to UTF8. Moodle requires that your Database is now UTF8 and will not upgrade if your database is not.

For more information about UTF8 have a look at the doc on unicode.


Tal vez vea el siguiente error al actualizar Moodle.

It is required that you store all your data in Unicode format (UTF-8). New installations must be performed into databases that have their default character set as Unicode. If you are upgrading, you should perform the UTF-8 migration process (see the Admin page).

Default Mysql character set

Moodle requiere el formato de codificación de caracteres UTF8 a fin de proporcionar un mejor soporte multilenguaje. Esto lo ha hecho desde Moodle 1.8, sin embargo la comprobación de UTF8 durante la instalación y actualización está implementada solamente a partir del Moodle 2.0. Debido a esto tal vez no puedas actualizar debido a que tu base de datos no ha sido configurada originalmente como utf8 al instalar por primera vez MySql o porque has estado usando Moodle desde antes de la versión 1.8 y no has convertido la base de datos previamente.

Cabe añadir que Mysql no ha sido hecho especificamente para Moodle. Mysql es un motor de bases de datos que es muy utilizado en proyectos Open Source, y en nuestro caso almacena todos los elementos de tu Moodle tales como nombres de usuario o punteros a todos los ficheros que hayan sido subidos.

Se precisan hacer dos cambios: 1) Actualizar MySql para tener el juego de caracteres UTF8 y 2) Actualizar la codificacion de la base de datos a UTF8

The descriptions elsewhere in this section cover making the utf8 database versions using mysqldump.

To make mysql default to utf8 you can edit /etc/my.cnf as follows.

(This was good for ubuntu server lucid 10.04 2.6.32-24-server Jan 2011)

In the client section of my.cnf

[client] ... .... ...

default-character-set=utf8 ....

and further down in my.cnf

[mysqld] ... ...





... ...

Having made your default character set utf, a mysqldump restore of your database with the --skip-character-set parameter, will restore the database with your new default character set of utf8.

utf8_unicode and utf8_general are not the same but similar. The difference is described in the unicode documentation page. (Link below)

Convirtiendo una base de datos vacía

If you have created your database schema and are receiving the error during your initial installation your Moodle database will still be empty. You can simply run the below query in your database to resolve the issue. alter database mydatabasename charset=utf8;

Convirtiendo una base de datos que contiene tablas

If you have previously installed Moodle and are now getting the error the following process will allow you to convert your database.

Linux y Mac

mysqldump -uusername -ppassword -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B dbname > dump.sql cp dump.sql dump-fixed.sql vim dump-fixed.sql


mysql -uusername -ppassword < dump-fixed.sql

or alternatively using sed:

  1. $1-dbusername $2-password $3-dbname

mysqldump -u$1 -p$2 -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B $3 > dump.sql sed -i.bak -e 's/DEFAULT CHARACTER SET latin1/DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci/' -e 's/DEFAULT CHARSET=latin1/DEFAULT CHARSET=utf8/' dump.sql mysql -u$1 -p$2 < dump.sql


The following steps will guide you in creating a database dump, editing the database dump so that the correct juego de caracteres (charset) y cotejamiento (collation) are used and then restoring the new database.

To start please open a new terminal and move to a temp directory.

mysqldump -uusername -ppassword -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B dbname > dump.sql

The first step is of course to dump out the database and of course we will use mysqldump for this. We do however need to set several arguments in order to clean up the charsets and provide a dump that is not going to cause you any problems if you are moving this database to a different database server or find yourself having to restore on a reverted system.

The username to access your database.
The password for the above user.
Complete inserts for better compatibility.
Extended inserts for better performance.
To set the default character set.
To reduce our workload if anything goes wrong.
Obviously not wanted or needed as we are changing it anyway.
Required so we can restore over the top of our existing database.
We use this option so that our dump will contain drop table and create table syntax (which we will change the syntax for).
The name of the database to convert.

When you run this command a database dump will be generated into dump.sql

Next step is to copy dump.sql to dump-fixed.sql achieved by

cp dump.sql dump-fixed.sql

We will make the desired changes within dump-fixed.sql and we will keep dump.sql as it is as a backup just in case.

vim dump-fixed.sql


Now we need to edit the dump and correct the incorrect charsets that have been used. I have chosen to do this with VIM however you can use any search+replace editor or program. ( I choose VIM for this only because every linux user is/should be familiar with it).

First we open the file using VIM, and then run the three commands.

The first command replaces all instances of DEFAULT CHARACTER SET latin1 with DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci. This is used to fix up the database's default charset and collation.

The second command replaces all instances of DEFAULT CHARSET=latin1 with DEFAULT CHARSET=utf8. This converts all tables from using latin1 to using UTF8.

The third command simply saves it and exits.

mysql -uusername -ppassword < dump-fixed.sql Now that we've made the required changes we simply need to restore the database over top of the existing database. We can do this by running the above command.


The following steps will let you create a database dump, edit it so that the correct charset (utf8) and collation (utf8_unicode_ci) are used, and then restore the new database. For this, you'll first have to download Super Sed (Win32 executable, zipped).

Start by opening a command window and move to a temporary folder.

[your mysql dir]\bin\mysqldump -u [username] -p[password] -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B [dbname] -r dbdump.sql
ssed -e "s/DEFAULT CHARACTER SET latin1/DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci/" dbdump.sql | ssed -e "s/DEFAULT CHARSET=latin1/DEFAULT CHARSET=utf8/" >dbdump_w.sql
[your mysql dir]\bin\mysql -u [username] -p[password] [dbname] < dbdump_w.sql

parámetros mysqldump

Username used to access your database.
Password for the above user.
-c (--complete-insert)
Creates INSERT statements that include column names.
-e (--extended-insert)
Uses a multiple-row INSERT syntax that includes several VALUES lists; this results in a smaller dump file and speeds up inserts when the file is reloaded.
Use and set utf8 as the default character set.
This option is useful only when using transactional tables such as InnoDB, as it helps minimize the locking time duration.
Suppress the SET NAMES statement (not needed because it is going to be changed).
Adds a DROP DATABASE statement before each CREATE DATABASE statement (to restore over the top of our existing database).
Adds a DROP TABLE statement before each CREATE TABLE statement.
-B (--databases)
Defines the name of the database to convert.
-r (--result-file)
This option should be used on Windows to prevent newline “\n” characters from being converted to “\r\n” carriage return/newline sequences. The result file is created and its previous contents overwritten, even if an error occurs while generating the dump.

Caracteres especiales no importarán correctamente

Under certain circumstances, when restoring UTF8 encoded mysql dump, international special chars (you are able to correctly see using, say, vim editor), does not appears to be imported correctly. In such cases you may want to try the following under a *nix system: 1.login into mysql, 2.create a db with utf8 encoding and 3. import your dump using 'source':

  1. cd /folder_where_your_dump_is/
  2. mysql -u your_user -p

> create database yourdb charset=utf8; > use yourdb; > SET NAMES 'utf8'; > source db_dump.sql > quit;

That should do the trick.

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