How to modify the character encoding in mysql

MySQL is a powerful relational database management system. In daily use, there may be a need for MySQL to modify the character encoding. This article will introduce how to modify character encoding in MySQL.

1. Determine the current character encoding

In MySQL, you can view the character encoding of the current database, table, and field through the following command:

SHOW VARIABLES LIKE 'character_set_database';
SHOW VARIABLES LIKE 'character_set_server';
SHOW VARIABLES LIKE 'collation_database';
SHOW VARIABLES LIKE 'collation_server';
SELECT CCSA.character_set_name AS character_set_database, CCSB.character_set_name AS character_set_server, 
CCSA.collation_name AS collation_database, CCSB.collation_name AS collation_server 
FROM information_schema.SCHEMATA S LEFT JOIN information_schema.COLLATION_CHARACTER_SET_APPLICABILITY CCSA ON 
S.DEFAULT_COLLATION_NAME = CCSA.collation_name LEFT JOIN information_schema.COLLATION_CHARACTER_SET_APPLICABILITY CCSB ON 
@@character_set_server = CCSB.character_set_name WHERE S.schema_name = 'database_name';

Among them, The first command is used to view the character set of the current database, the second command is used to view the character set of the MySQL server, the third command is used to view the collation rules of the current database, and the fourth command is used to view the collation of the MySQL server. Rules, the fifth command is used to view the character set and collation rules of the specified database.

If you need to view the character encoding of a certain table or field, you can use the following command:

SHOW CREATE TABLE table_name;

This command will return the data definition language (DDL) of the specified table, including the Character set and collation rule information for all fields in the table.

2. Modify character encoding

If you need to modify the character encoding of the current database, you can use the following command:

ALTER DATABASE database_name CHARACTER SET new_character_set_name;

Among them, database_name is the name of the database that needs to be modified, new_character_set_name is the name of the new character set.

If you need to modify the character encoding of a certain table or field, you can use the following command:

ALTER TABLE table_name CONVERT TO CHARACTER SET charset_name COLLATE collation_name;

Among them, table_name is the name of the table that needs to be modified, charset_name is the new character set name, collation_name is the new collation rule name. It should be noted that modifying the character encoding of a table will affect the character encoding of all fields in the table.

3. Set the default character encoding

If you need to set the default character encoding of the MySQL server, you can add the following to the MySQL configuration file my.cnf Content:

[mysqld]
character_set_server=utf8mb4
collation_server=utf8mb4_unicode_ci

Among them, character_set_server is the default character set name of the server, and collation_server is the default collation rule name of the server.

4. Summary

MySQL is a widely used database management system. During use, the character encoding needs to be modified. This article introduces how to modify the character encoding in MySQL, including viewing the current character encoding, modifying the character encoding, and setting the default character encoding. It should be noted that modifying the character encoding may affect data storage and reading, so you should operate with caution.

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