How do I go about specifying and using an ENUM in a Django model?
Specifying a mySQL ENUM in a Django model
From the Django documentation:
MAYBECHOICE = ( ('y', 'Yes'), ('n', 'No'), ('u', 'Unknown'), )
And you define a charfield in your model :
married = models.CharField(max_length=1, choices=MAYBECHOICE)
You can do the same with integer fields if you don't like to have letters in your db.
In that case, rewrite your choices:
MAYBECHOICE = ( (0, 'Yes'), (1, 'No'), (2, 'Unknown'), )
choices parameter won't use the ENUM db type; it will just create a VARCHAR or INTEGER, depending on whether you use
choices with a CharField or IntegerField. Generally, this is just fine. If it's important to you that the ENUM type is used at the database level, you have three options:
- Use "./manage.py sql appname" to see the SQL Django generates, manually modify it to use the ENUM type, and run it yourself. If you create the table manually first, "./manage.py syncdb" won't mess with it.
- If you don't want to do this manually every time you generate your DB, put some custom SQL in appname/sql/modelname.sql to perform the appropriate ALTER TABLE command.
- Create a custom field type and define the db_type method appropriately.
With any of these options, it would be your responsibility to deal with the implications for cross-database portability. In option 2, you could use database-backend-specific custom SQL to ensure your ALTER TABLE is only run on MySQL. In option 3, your db_type method would need to check the database engine and set the db column type to a type that actually exists in that database.
UPDATE: Since the migrations framework was added in Django 1.7, options 1 and 2 above are entirely obsolete. Option 3 was always the best option anyway. The new version of options 1/2 would involve a complex custom migration using
SeparateDatabaseAndState -- but really you want option 3.
There're currently two github projects based on adding these, though I've not looked into exactly how they're implemented:
Provides an enumeration Django model field (using IntegerField) with reusable enums and transition validation.
This package lets you use real Python (PEP435-style) enums with Django.
I don't think either use DB enum types, but they are in the works for first one.