/Python/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 vote180 views1 answer
Set xlim histogram python
Python
1 vote166 views1 answer
How to convert ton to kg using python
Python
0 vote168 views1 answer
Create folders with subfolders python
Python
0 vote266 views1 answer
How to add array and array in python
Python
0 vote180 views1 answer
How to print the fibonacci sequence in python using while loop
Python
0 vote197 views1 answer
Django allauth Reverse for 'password_reset_confirm' not found. 'password_reset_confirm' is not a valid view function or pattern name.
Python
0 vote189 views1 answer
Drawing diff circles with random radius in diff positions .
Python
19 votes179 views10 answers
Gme
Python
17 votes175 views2 answers
WARNING: You are using pip version 19.2.3, however version 21.2.4 is available.
Python
0 vote165 views1 answer
Write a python program which accepts the user
Python