How do I change a MySQL table to UTF-8?

Question

I know there are many settings for a language for a table and a database.

I already created the database. I believe when I created it, it was default/LATIN. I want to change everything-I mean...both the table and the database, to UTF-8.

How can I do that? thanks.

Answer 1

aioobe's answer tells how to change the character set of a database, table or column. You should keep in mind that

• setting the character set for a table just specifies the default character set for new columns in that table. It doesn't change the character set for preexisting columns; you have to do those columns individually, OR if you want to change every single string-type column in the table to the same character set there's a command you can use to do that: "alter table ... convert to character set" ( http://dev.mysql.com/doc/refman/5.1/en/alter-table.html )

• if you already have data that is stored mis-encoded in a column, then using "alter table ... modify" to change the column will not quite solve the problem. For example, if you're been storing UTF-8 data in a Latin1 column and you change the character set directly from Latin1 to UTF-8, it'll still be mis-encoded afterwards. This can be worked around by converting from Latin-1 to UTF-8 via binary.

Answer 2

Add to your my.cnf this:

[mysqld]
character-set-server=utf8
default-collation=utf8_unicode_ci

And restart mysqld deamon.

ADDED:

ALTER DATABASE your_base_name CHARACTER SET utf8 COLLATE utf8_unicode_ci;

and my.cnf

SET collation_connection     = utf8_unicode_ci;
SET character_set_results    = utf8;
SET character_set_connection = utf8;
SET character_set_client     = utf8;

Answer 3

Have a look at Using alter command to change character set.

Another useful link: http://dev.mysql.com/doc/refman/5.0/en/charset-table.html

The general form is

ALTER DATABASE db_name
    [[DEFAULT] CHARACTER SET charset_name]
    [[DEFAULT] COLLATE collation_name]

and for a specific column in a table

ALTER TABLE column COLLATE utf8_general_ci

---

• MySQL’s character sets and collations demystified
• MySQL Forums :: Change Collation

Answer 4

1) Database default character set and collation:

SELECT @@character_set_database, @@collation_database;

Altered via: ALTER DATABASE CHARACTER SET utf8 COLLATE utf8_general_ci;

2) Table default character set and collation:

SELECT T.table_name, 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 = "YOUR_DB";`

Altered via: ALTER TABLE [table_name] CHARACTER SET utf8 COLLATE utf8_general_ci

3) Column character set and collation:

SELECT c.TABLE_NAME, c.COLUMN_NAME, c.CHARACTER_SET_NAME, c.COLLATION_NAME 
FROM information_schema.COLUMNS c
WHERE c.table_schema = "YOUR_DB";`

Altered via: ALTER TABLE [table_name] CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci

The third one requires that you disable foreign key checks for the data conversion. So putting this all together:

DELIMITER //
CREATE PROCEDURE migrate_charset_to_utf8()
  BEGIN
    DECLARE done TINYINT DEFAULT 0;
    DECLARE curr_table VARCHAR(64);

    DECLARE table_cursor CURSOR FOR
    SELECT T.table_name
      FROM information_schema.TABLES T
      WHERE T.TABLE_TYPE = 'BASE TABLE' AND
        T.TABLE_SCHEMA = 'YOUR_DB';
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

    OPEN table_cursor;

    table_loop: LOOP
      FETCH table_cursor INTO curr_table;
      IF done THEN
        LEAVE table_loop;
      END IF;

      # Convert table data(columns) charset
      SET @sql_str1 = CONCAT("ALTER TABLE ", curr_table, " CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci");
      PREPARE stmt1 FROM @sql_str1;
      EXECUTE stmt1;
      DEALLOCATE PREPARE stmt1;

      # Set table's default charset e.g for new columns added
      SET @sql_str2 = CONCAT("ALTER TABLE ", curr_table, " CHARACTER SET utf8 COLLATE utf8_general_ci");
      PREPARE stmt2 FROM @sql_str2;
      EXECUTE stmt2;
      DEALLOCATE PREPARE stmt2;

    END LOOP table_loop;

    CLOSE table_cursor;
  END//

DELIMITER ;


SET @@FOREIGN_KEY_CHECKS = 0;
CALL migrate_charset_to_utf8();
SET @@FOREIGN_KEY_CHECKS = 1;

ALTER DATABASE CHARACTER SET utf8 COLLATE utf8_general_ci;

EDIT: look here instead

Answer 5

ALTER TABLE tbl_name CONVERT TO CHARACTER SET utf8;