/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

0 vote202 views2 answers
Django serializer method field read write
Python Django
0 vote191 views2 answers
MultiValueDictKeyError django
Python Django
1 vote199 views2 answers
No changes detected in app django
Python Django
0 vote203 views1 answer
How to log errors while debug is false in django
Python Django
17 votes189 views6 answers
Django model
Python Django
1 vote202 views1 answer
Only include top ten items django for loop
Python Django
0 vote174 views1 answer
Django get all model fields
Python Django
2 votes195 views3 answers
How to set indian timezone in django
Python Django
4 votes185 views1 answer
Django is null
Python Django
1 vote182 views1 answer
User matching query does not exist. django
Python Django