/Python/Django/Unique mark boolean django model field

Unique mark boolean django model field

#FIELDS.py

from django.db.models import BooleanField


class UniqueBooleanField(BooleanField):
    def pre_save(self, model_instance, add):
        objects = model_instance.__class__.objects
        # If True then set all others as False
        if getattr(model_instance, self.attname):
            objects.update(**{self.attname: False})
        # If no true object exists that isnt saved model, save as True
        elif not objects.exclude(id=model_instance.id)\
                        .filter(**{self.attname: True}):
            return True
        return getattr(model_instance, self.attname)

# To use with South
from south.modelsinspector import add_introspection_rules
add_introspection_rules([], ["^project\.apps\.fields\.UniqueBooleanField"])


#Models.py
from django.db import models

from project.apps.fields import UniqueBooleanField


class UniqueBooleanModel(models.Model):
    unique_boolean = UniqueBooleanField()

    def __unicode__(self):
        return str(self.unique_boolean)

Source: stackoverflow.com

Similar codes

14 votes253 views2 answers
Django static files / templates
Python Django
0 vote247 views1 answer
Current page django
Python Django
1 vote263 views3 answers
Making ckeditor django responsive
Python Django
1 vote236 views1 answer
Db_index django
Python Django
1 vote257 views1 answer
Django making a custom 403 page
Python Django
1 vote223 views1 answer
Using regex validators in django models
Python Django
1 vote282 views1 answer
How to add captcha in django forms
Python Django
0 vote270 views1 answer
How to get session value in django template
Python Django
0 vote234 views2 answers
Django run manage.py from python
Python Django
1 vote237 views1 answer
Django round 2 decimal
Python Django