MySQL 8 Issue: UTF-8 characters are not displayed correctly

Introduction

MySQL 8 has introduced many improvements and rigor in the ways it handles character representation, which includes full support for UTF-8 encoding. While this is generally beneficial, it can lead to issues when the database or the connections are not properly configured to handle UTF-8. Characters may not display correctly, leading to data integrity concerns. This tutorial walks you through some common solutions to address this issue.

Solutions

Several strategies can be applied to ensure the correct display of UTF-8 characters in MySQL 8. These range from configuring the server and client environment to monitoring data imports and application-layer adjustments.

Solution 1: Configure Server for UTF-8

One of the first steps to ensure UTF-8 characters display correctly is to configure your MySQL server to use UTF-8 as the default character set.

• Step 1: Open my.cnf (or my.ini on Windows) MySQL configuration file.
• Step 2: Under the [mysqld] section, set the following:

  [mysqld]
  character-set-server=utf8mb4
  collation-server=utf8mb4_unicode_ci
  

• Step 3: Restart the MySQL server to apply changes.

Notes: Using utf8mb4 charset ensures support for a wider range of Unicode characters compared to utf8. The utf8mb4_unicode_ci collation is recommended for a more accurate string comparison.

Solution 2: Setting Client Connection Encoding

The client application must set the character set to UTF-8 when it connects to MySQL. This ensures that the communication between your application and the database server interprets strings as UTF-8.

• Step 1: Identify the connection string or data source setup within your application’s configuration.
• Step 2: Add the character set as a parameter in connection settings. For example, in a PHP data source name (DSN), include charset=utf8mb4.
• Step 3: In some programming languages, set the character encoding after making a connection, for example with the mysqli_set_charset() function in PHP: $mysqli->set_charset("utf8mb4");

Notes: This is a critical step that is often overlooked. Not setting the client character set can lead to issues even if the server is properly configured, especially in scenarios where the client and server are using different default character sets.

Solution 3: Verify Table and Column Character Set

Ensure the individual database tables and columns are using the utf8mb4 character set. An incorrectly configured table or column can override server settings.

Step 1: Check the current character set of the table with the following SQL command:

SHOW CREATE TABLE my_table;  

Step 2: If the table is not using utf8mb4, alter it using an SQL ALTER TABLE statement:

ALTER TABLE my_table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;  

Notes: Be careful when changing table encodings on large production databases, as it can be time-consuming and lock tables. Always backup your database before making schema changes.

Solution 4: Ensure Proper Import and Export

When importing or exporting data, it’s essential to set the correct character encoding. This is particularly true for tools like mysqldump, LOAD DATA INFILE, or external applications exporting data.

• Step 1: Use the –default-character-set option in mysqldump to specify the character set:
• mysqldump --default-character-set=utf8mb4 ...
• Step 2: For LOAD DATA INFILE, ensure the database’s character set is set as utf8mb4 before running the command.

Notes: Encoding issues can often stem from an incorrect import process that misinterprets the character set, so getting this step right can prevent future issues.

Conclusion

In summary, displaying UTF-8 characters correctly in MySQL 8 involves checking the server, client, and table configurations, as well as ensuring proper data importing and exporting procedures. By following the outlined solutions, you should be able to mitigate issues with character encoding and maintain the integrity of your data.