Converting a MySQL database to UTF-8

This article describes how to convert a MySQL database’s character set to UTF-8 encoding (also known as Unicode). The UTF-8 character encoding set supports many alphabets and characters for a wide variety of languages. Although MySQL supports the UTF-8 character encoding set, it is often not used as the default character set during database and table creation. As a result, many databases use the Latin character set, which can be limiting depending upon the application.

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Determining the current character encoding set

To determine which character encoding set a MySQL database or table is currently using:

1. Log in to your account using SSH.
2. At the command line, type the following command, replacing username with your username:
   mysql -u username -p
   
3. At the Enter Password prompt, type your password. When you type the correct password, the mysql> prompt appears.
4. To display the current character encoding set for a particular database, type the following command at the mysql> prompt. Replace dbname with the database name:
   SELECT default_character_set_name FROM information_schema.SCHEMATA S WHERE schema_name = "dbname";
   
5. To display the current character encoding set for a particular table in a database, type the following command at the mysql> prompt. Replace dbname with the database name, and tablename with the name of the table:
   SELECT CCSA.character_set_name FROM information_schema.`TABLES` T,information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` CCSA WHERE CCSA.collation_name = T.table_collation AND T.table_schema = "dbname" AND T.table_name = "tablename";
   
6. To exit the mysql program, type \q at the mysql> prompt.

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Converting the character encoding set to UTF-8

To convert the character encoding set to UTF-8:

1. Log in to your account using SSH.
2. Create a text file named .my.cnf. To do this, you can use a text editor such as Vim or Nano. This procedure shows how to use Nano. At the command line, type the following command:
   nano .my.cnf
   
3. Add the following lines to the file, replacing username with your username and password with your password (make sure the password is enclosed in quotation marks):
   [client]
   user=username
   password="password"
   
4. When the edits are complete, press Ctrl+X, type y to save the file, and then press Enter.
5. To change the character set encoding to UTF-8 for all of the tables in the specified database, type the following command at the command line. Replace dbname with the database name:
   mysql --database=dbname -B -N -e "SHOW TABLES" | awk '{print "SET foreign_key_checks = 0; ALTER TABLE", $1, "CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci; SET foreign_key_checks = 1; "}' | mysql --database=dbname
   
6. After the command finishes, type the following command to start the mysql program:
   mysql
   
7. To change the character set encoding to UTF-8 for the database itself, type the following command at the mysql> prompt. Replace dbname with the database name:
   ALTER DATABASE dbname CHARACTER SET utf8 COLLATE utf8_general_ci;
   
8. To exit the mysql program, type \q at the mysql> prompt.
9. To delete the .my.cnf file, type the following command at the command line:
   rm .my.cnf
   
10. To verify that the character set encoding is now set to UTF-8, follow the steps in the Determining the current character encoding set procedure above.

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More information

For more information about UTF-8 and Unicode, please visit http://en.wikipedia.org/wiki/UTF-8.

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Related articles

• Connecting to MySQL from the command line
• Managing MySQL databases, users, and tables from the command line