What are the tips for learning MySQL's character set and collation settings?

What are the tips for learning MySQL’s character set and collation settings?

MySQL is a popular relational database management system. When processing data, the settings of character sets and collation rules are very important. Properly setting character sets and collation rules can ensure data integrity and consistency, while also improving query and sorting efficiency. This article will introduce some tips for learning MySQL character set and collation settings, and provide corresponding code examples.

1. Character set setting skills

1. View the current character set settings

Use the following command to view the default character set and collation of the current MySQL server :

SHOW VARIABLES LIKE 'character_set%';

Among them, character_set_server represents the default character set of the server, character_set_database represents the default character set of the current database, and character_set_connection represents the default character set of the current session.

2. Modify the character set settings

If you need to modify the character set settings of MySQL, you can do it through the following steps:

(1) Modify the configuration file

Open the MySQL configuration file my.cnf (Windows systems are generally located in the bin folder under the MySQL installation directory, Linux systems are generally located in /etc/my.cnf), find the [mysqld] tag, and add or Modify the following two configuration items:

[mysqld]
character_set_server=utf8
collation_server=utf8_general_ci

character_set_server specifies the default character set of the server, and collation_server specifies the default collation of the server.

(2) Restart the MySQL server

After modifying the configuration file, you need to restart the MySQL server for the modification to take effect.

3. Modify the character set of the database

In MySQL, each database has its own default character set. If you need to modify the character set of the database, you can use the following command:

ALTER DATABASE database_name CHARACTER SET charset_name COLLATE collation_name;

Among them, database_name is the database name to be modified, charset_name is the character set to be set, and collation_name is the collation rule to be set.

4. Modify the character set and collation rules of the table

Each table can also have its own character set and collation rules. You can use the following command to modify the character set and collation of the table:

ALTER TABLE table_name CONVERT TO CHARACTER SET charset_name COLLATE collation_name;

Among them, table_name is the name of the table to be modified, charset_name and collation_name are the character set and collation to be set respectively.

2. Sorting rule setting skills

1. Types of sorting rules

MySQL supports multiple sorting rules, the common ones are: utf8_general_ci (size-insensitive Write, do not consider accent marks), utf8_unicode_ci (not case sensitive, consider accent marks), utf8_bin (case sensitive). Appropriate sorting rules need to be selected according to specific application scenarios.

2. Modify collation settings

When creating a table, you can set the collation of the table by specifying the character set and collation. For example, an example of creating a table that uses the utf8 character set and uses the utf8_general_ci collation:

CREATE TABLE table_name (
    column_name1 data_type1 CHARACTER SET utf8 COLLATE utf8_general_ci,
    column_name2 data_type2 CHARACTER SET utf8 COLLATE utf8_general_ci,
    ...
) ENGINE = engine_type DEFAULT CHARSET = utf8 COLLATE = utf8_general_ci;

Among them, table_name is the table name of the new table, column_name1 and column_name2 are the field names of the table, data_type1 and data_type2 are the field names Data type, engine_type is the storage engine of the table (such as InnoDB, MyISAM, etc.).

3. Code Example

The following is a complete example showing how to create a table using the utf8 character set and utf8_general_ci collation:

CREATE TABLE mytable (
    id INT(11) PRIMARY KEY,
    name VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_general_ci
) ENGINE = InnoDB DEFAULT CHARSET = utf8 COLLATE = utf8_general_ci;

The above example creates a The table named mytable contains two fields: id and name. Among them, the id field is an integer, used as the primary key, and the name field is a character, using the utf8 character set and utf8_general_ci sorting rules.

Summary:

Through the above introduction, we can learn some tips about MySQL character set and collation setting. Correctly setting the character set and sorting rules can ensure the integrity and consistency of data and improve query and sorting efficiency. In actual applications, appropriate character sets and sorting rules need to be selected according to specific needs and scenarios.

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