MySQL Character Set Considerations in Django

Based on the information provided in the Django 5.1 documentation, I can offer some thoughts on your proposal to change Django's default character set from utf8 to utf8mb4 for MySQL databases.

Current Documentation Context

The Django documentation currently shows that when creating a database, it recommends:

SQLCopied
CREATE DATABASE <dbname> CHARACTER SET utf8;

This ensures all tables and columns use UTF-8 by default. The documentation also mentions collation settings, with utf8_general_ci being the default collation for UTF-8 databases in MySQL, which performs case-insensitive comparisons.

Regarding Your Proposal

Your proposal to change Django's default from utf8 (utf8mb3) to utf8mb4 aligns with MySQL's own recommendations since version 8.0. This would be beneficial for several reasons:

1. Full Unicode Support: utf8mb4 supports the full Unicode character set including emojis and certain special characters that utf8mb3 cannot handle.

2. Future Compatibility: Since utf8mb3 is deprecated in MySQL 8.0+, moving to utf8mb4 would align Django with MySQL's direction.

3. Backward Compatibility: Your approach of allowing users to explicitly specify utf8mb3 for legacy databases through the DATABASES configuration provides a good migration path.

The configuration example you provided is correct and demonstrates how users can specify charset and collation settings:

PYTHONCopied
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'mydatabase',
        'USER': 'myuser',
        'PASSWORD': 'mypassword',
        'HOST': 'localhost',
        'PORT': '3306',
        'OPTIONS': {
            'charset': 'utf8mb4',
            'collation': 'utf8mb4_unicode_ci',
        },
    }
}

Considerations

When implementing this change, it would be important to:

1. Document the change clearly in release notes
2. Provide migration guidance for existing databases
3. Consider potential impacts on string length constraints (utf8mb4 can require more storage space)
4. Address any performance implications, as noted in the documentation regarding collation choices

This proposal seems to be a forward-thinking change that would benefit Django users by aligning with MySQL's current best practices while maintaining compatibility with existing applications.