Ascii and UTF-8 encoding for MySql: How to compress and convert MySQL's character encoding

In the MySQL database, character encoding is a very important concept. Character encoding refers to the way characters are mapped into binary data. There are many types of character encodings supported in MySQL, the most commonly used ones are Ascii encoding and UTF-8 encoding. These two character encodings play a very important role in MySQL, because data in MySQL is stored in character form, and the choice of character encoding may affect the performance and space of the database.

Ascii encoding is an encoding method based on Latin letters. It can only represent 128 characters, including uppercase and lowercase letters, numbers, and some special characters. Ascii encoding is sufficient for Western languages ​​such as English, but for text such as Chinese, Ascii encoding cannot meet the needs.

UTF-8 encoding is a Unicode encoding method that can represent all characters in the world. UTF-8 encoding uses 1 to 4 bytes to represent a character, of which ASCII characters use 1 byte and non-ASCII characters use 2 to 4 bytes. UTF-8 encoding has good compatibility because it can represent all characters, so it can completely replace Ascii encoding.

In MySQL, strings encoded using Ascii will take up less space than strings encoded using UTF-8. This is because Ascii encoding only requires 1 byte to represent a character, while UTF-8 encoding may require 2 to 4 bytes to represent a character. When using Ascii encoding, MySQL can use less space to store data, thereby improving database performance and space utilization.

However, when it comes to multilingual text, Ascii encoding is insufficient. At this time, using UTF-8 encoding becomes more appropriate. Although UTF-8 encoding takes up more space, it can represent all characters, making it more suitable in multi-language environments.

In MySQL, you can specify which encoding method to use by setting the character set. When creating a database or table, you can specify the character set and collation to be used. If not specified, the default is to use the character set and collation of the database server.

In MySQL, you can use the following statement to modify the character set of the database to UTF-8 encoding:

ALTER DATABASE database_name CHARACTER SET utf8;

This statement will change the database character set to UTF-8. The character set is modified to UTF-8 encoding.

In MySQL, you can use the following statement to modify the character set of the table to UTF-8 encoding:

ALTER TABLE table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

This This statement changes the character set and collation of the table to UTF-8 encoding.

In MySQL, if you need to convert an Ascii-encoded string into a UTF-8-encoded string, you can use the following statement:

SELECT CONVERT(column_name USING utf8) FROM table_name;

This statement converts the character set of the specified column from Ascii encoding to UTF-8 encoding.

If you need to convert a UTF-8 encoded string into an Ascii encoded string, you can use the following statement:

SELECT CONVERT(column_name USING ascii) FROM table_name;

This statement converts the character set of the specified column from UTF-8 encoding to Ascii encoding.

When using a MySQL database, it is very important to correctly understand character encoding. Properly selecting and converting character encodings can improve database performance and space utilization, thereby better supporting multi-language applications.

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