/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

1 vote201 views2 answers
Django timezone settings
Python Django
0 vote219 views1 answer
Django serializer,
Python Django
5 votes226 views4 answers
Django get or 404
Python Django
10 votes237 views2 answers
Adding static file and its usage in Django
Python Django
0 vote294 views1 answer
|safe django
Python Django
0 vote227 views1 answer
Celery beat command for django celery beat
Python Django
0 vote217 views1 answer
Django jinja else if template tags
Python Django
0 vote213 views1 answer
Django cms api create page
Python Django
2 votes222 views1 answer
Django template capitalize equivalent
Python Django
0 vote240 views1 answer
Django.core.exceptions.FieldError: 'date' cannot be specified for Forum model form as it is a non-editable field
Python Django