/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 vote295 views1 answer
Import ArraField django
Python Django
0 vote349 views1 answer
How to compress image field in django?
Python Django
0 vote392 views1 answer
Django 3 create async rest api
Python Django
0 vote335 views1 answer
Django related_name abstract class
Python Django
0 vote336 views3 answers
How to create a User and User profile in django rest framework
Python Django
0 vote355 views1 answer
Add url parameter in anchor django template
Python Django
1 vote331 views1 answer
How to redirect to previous page in django
Python Django
6 votes313 views3 answers
Django filter install
Python Django
2 votes346 views1 answer
Django get current date
Python Django
-2 votes324 views6 answers
Django download
Python Django