python - Case insensitive unique model fields in Django?

Question

I have basically a username is unique (case insensitive), but the case matters when displaying as provided by the user.

I have the following requirements:

• field is CharField compatible
• field is unique, but case insensitive
• field needs to be searchable ignoring case (avoid using iexact, easily forgotten)
• field is stored with case intact
• preferably enforced on database level
• preferably avoid storing an extra field

Is this possible in Django?

The only solution I came up with is "somehow" override the Model manager, use an extra field, or always use 'iexact' in searches.

I'm on Django 1.3 and PostgreSQL 8.4.2.

Answer 1

As of Django 1.11, you can use CITextField, a Postgres-specific Field for case-insensitive text backed by the citext type.

from django.db import models
from django.contrib.postgres.fields import CITextField

class Something(models.Model):
    foo = CITextField()

Django also provides CIEmailField and CICharField, which are case-insensitive versions of EmailField and CharField.