EnumField

Using a CharField with a limited set of strings leads to inefficient data storage since the string value is stored over and over on disk. MySQL’s ENUM type allows a more compact representation of such columns by storing the list of strings just once and using an integer in each row to refer to which string is there. EnumField allows you to use the ENUM type with Django.

Docs: MySQL / MariaDB.

class django_mysql.models.EnumField(choices, **kwargs)

A subclass of Django’s Charfield that uses a MySQL ENUM for storage.

choices is a standard Django argument for any field class, however it is required for EnumField. It can either be a list of strings, or a list of two-tuples of strings, where the first element in each tuple is the value used, and the second the human readable name used in forms. The best way to form it is with Django’s TextChoices enumeration type.

For example:

from django.db import models
from django_mysql.models import EnumField


class BookCoverColour(models.TextChoices):
    RED = "red"
    GREEN = "green"
    BLUE = "blue"


class BookCover(models.Model):
    colour = EnumField(choices=BookCoverColour.choices)

Warning

It is possible to append new values to choices in migrations, as well as edit the human readable names of existing choices.

However, editing or removing existing choice values will error if MySQL Strict Mode is on, and replace the values with the empty string if it is not.

Also the empty string has strange behaviour with ENUM, acting somewhat like NULL, but not entirely. It is therefore recommended you ensure Strict Mode is on.