For applications that store data using the default MySQL character set and collation (
latin1_swedish_ci), no special configuration should be needed. If applications
require data storage using a different character set or collation, you can configure character set information
Specify character settings per database. For example, applications that use one
database might require
utf8, whereas applications that use another database
Specify character settings at server startup. This causes the server to use the given settings for all applications that do not make other arrangements.
Specify character settings at configuration time, if you build MySQL from source. This causes the server to use the given settings for all applications, without having to specify them at server startup.
When different applications require different character settings, the per-database technique provides a good deal of flexibility. If most or all applications use the same character set, specifying character settings at server startup or configuration time may be most convenient.
For the per-database or server-startup techniques, the settings control the character set for data storage. Applications must also tell the server which character set to use for client/server communications, as described in the following instructions.
The examples shown here assume use of the
utf8 character set and
Specify character settings per database. To create a database such
that its tables will use a given default character set and collation for data storage, use a
CREATE DATABASE statement like this:
CREATE DATABASE mydb DEFAULT CHARACTER SET utf8 DEFAULT COLLATE utf8_general_ci;
Tables created in the database will use
by default for any character columns.
Applications that use the database should also configure their connection to the server each time they connect.
This can be done by executing a
SET NAMES 'utf8' statement after connecting. The
statement can be used regardless of connection method: The mysql client, PHP scripts, and so forth.
In some cases, it may be possible to configure the connection to use the desired character set some other way.
For example, for connections made using mysql, you can specify the
--default-character-set=utf8 command-line option to achieve the same effect as
SET NAMES 'utf8'.
For more information about configuring client connections, see Section 10.1.4, "Connection Character Sets and Collations".
If you change the default character set or collation for a database, stored routines that use the database
defaults must be dropped and recreated so that they use the new defaults. (In a stored routine, variables with
character data types use the database defaults if the character set or collation are not specified explicitly.
See Section 13.1.12, "
CREATE FUNCTION Syntax".)
Specify character settings at server startup. To select a character
set and collation at server startup, use the
--collation-server options. For example, to specify the options in an option
file, include these lines:
These settings apply server-wide and apply as the defaults for databases created by any application, and for tables created in those databases.
It is still necessary for applications to configure their connection using
NAMES or equivalent after they connect, as described previously. You might be tempted to start the server
NAMES 'utf8'" option to cause
SET NAMES to be executed automatically
for each client that connects. However, this will yield inconsistent results because the
init_connect value is not executed for users who have the
Specify character settings at MySQL configuration time. To select a
character set and collation when you configure and build MySQL from source, use the
DEFAULT_COLLATION options for CMake:
cmake . -DDEFAULT_CHARSET=utf8 \
The resulting server uses
the default for databases and tables and for client connections. It is unnecessary to use
--collation-server to specify those defaults at server startup. It is also
unnecessary for applications to configure their connection using
SET NAMES or
equivalent after they connect to the server.
Regardless of how you configure the MySQL character set for application use, you must also consider the
environment within which those applications execute. If you will send statements using UTF-8 text taken from a
file that you create in an editor, you should edit the file with the locale of your environment set to UTF-8 so
that the file encoding is correct and so that the operating system handles it correctly. If you use the mysql client from within a terminal window, the window must
be configured to use UTF-8 or characters may not display properly. For a script that executes in a Web
environment, the script must handle character encoding properly for its interaction with the MySQL server, and
it must generate pages that correctly indicate the encoding so that browsers know how to display the content of
the pages. For example, you can include this
<meta> tag within your
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />