Django 2.2 added a new constraints API which makes addressing this case much easier within the database. You will need two constraints: The existing tuple constraint; and The remaining keys minus the nullable key, with a condition If you have multiple nullable fields, I guess you will need to handle the permutations. Here’s an example … Read more
You might actually look into the internationally standardized format E.164, recommended by Twilio for example (who have a service and an API for sending SMS or phone-calls via REST requests). This is likely to be the most universal way to store phone numbers, in particular if you have international numbers work with. Phone by PhoneNumberField … Read more
AFAIK, this is because of backwards compatibility. There are also problems with ModelForms with excluded fields, models with default values, pre_save() signals, etc. Sources you might be intrested in: http://code.djangoproject.com/ticket/13100 http://groups.google.com/group/django-developers/browse_frm/thread/b888734b05878f87
You can use Django’s built-in validators— from django.db.models import IntegerField, Model from django.core.validators import MaxValueValidator, MinValueValidator class CoolModelBro(Model): limited_integer_field = IntegerField( default=1, validators=[ MaxValueValidator(100), MinValueValidator(1) ] ) Edit: When working directly with the model, make sure to call the model full_clean method before saving the model in order to trigger the validators. This is not … Read more