Chinese garbled characters in mysql

MySQL database system is a popular open source relational database management system that is often used in many large websites and applications. However, when using MySQL Chinese data, you may encounter the problem of Chinese garbled characters. Chinese garbled characters means that when inserting or querying Chinese characters in MySQL, the characters cannot be displayed normally, and symbols such as garbled characters or question marks often appear. In this article, we will discuss the causes and solutions of Chinese garbled characters in MySQL database.

1. The reason why MySQL Chinese garbled characters

1.1 The character set settings of the database and the data table are inconsistent

In MySQL, the character set and sorting of strings Rules are defined by the character set and collation of the data table. If the character set settings of the database and data table are inconsistent, it may cause Chinese garbled characters.

1.2 Database connection character set settings are inconsistent

When the MySQL client connects to the server, it also needs to set the character set, otherwise it will cause Chinese garbled characters. If the character sets set when the server and client connect are inconsistent, the problem of Chinese garbled characters will occur.

1.3 The character set settings of the database server and the operating system are inconsistent

If the character set settings of the database server and the operating system are inconsistent, it may also cause Chinese garbled characters.

2. Solution

2.1 Set the correct character set and sorting rules

In MySQL, correctly setting the character set and sorting rules is the solution to Chinese garbled characters The key step to the problem. We can set it up through the following steps:

1. View the character set and sorting rules of the database and data table:

SHOW CREATE DATABASE database_name;
SHOW CREATE TABLE table_name;

2. Modify the character set and sorting of the data table Rules:

ALTER TABLE table_name CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

3. Modify the MySQL client connection character set:

When connecting to the MySQL server, set the character set:

mysql --default-character-set=utf8mb4 -h host -u user -p

4. Modify the database server and operating system character set:

Modify the my.cnf configuration file of the MySQL server and set the following parameters:

[client]
default-character-set=utf8mb4

[mysqld]
character-set-server=utf8mb4

After restarting the MySQL service, you can solve the problem of Chinese Garbled code problem.

2.2 Modify the application code

If there is still a Chinese garbled problem, we need to check whether the Chinese characters are processed correctly in the application code. In languages ​​such as PHP and Java, we should ensure that the character set is set correctly and use UTF-8 encoding. Common methods for dealing with Chinese character problems are:

1. In PHP, use the header() function to set the character set:

header('Content-Type:text/html;charset=utf-8');

2. In Java, by setting HTTP The content-type header of the response displays the correctly encoded page:

response.setContentType("text/html;charset=utf-8");

The above is a way to solve the problem of Chinese garbled characters in MySQL by correctly setting the character set and collation rules, client connection character set, and Modifying the application code can avoid the problem of Chinese garbled characters. Of course, in actual project development, you may encounter more Chinese processing problems, which need to be dealt with based on specific circumstances. We should develop good coding habits, correctly handle Chinese characters in projects, and ensure the correctness and reliability of applications.

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