Django: Change the parent, when the child get deleted(unidirectional OneToOne)

Question

I want to change Photo 'labeled' field False when I delete LabeledPhoto object.

#models.py
class Photo(models.Model):
    image = models.ImageField(upload_to='shoes_data/%Y/%m/%d', name='image')
    created = models.DateTimeField(auto_now_add=True)
    labeled = models.BooleanField(default=False)

class LabeledPhoto(models.Model):
    labeled_image = models.OneToOneField(Photo, on_delete=models.PROTECT, related_name='labeled_image')
    topcategory = models.CharField(max_length=64)
    subcategory = models.CharField(max_length=64)
    labeler = models.CharField(max_length=32)
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

I tried like this but, It didn't work

# views.py
class LabeledPhotoDelete(DeleteView):
    model = LabeledPhoto
    template_name = 'label/labeled_photo_delete.html'
    success_url = reverse_lazy('photo:labeled_list')

    def delete(self, request, *args, **kwargs):
        self.object = self.get_object()
        success_url = self.get_success_url()
        labeled = LabeledPhoto.objects.get(id=self.object.pk)
        labeled.labeled_image.labeled = False
        labeled.save()
        self.object.delete()
        return reverse(success_url)

Answer 1

You need to .save() the Photo:

from django.http import HttpResponseRedirect

class LabeledPhotoDelete(DeleteView):
    model = LabeledPhoto
    template_name = 'label/labeled_photo_delete.html'
    success_url = reverse_lazy('photo:labeled_list')

    def delete(self, request, *args, **kwargs):
        self.object = self.get_object()
        success_url = self.get_success_url()
        image = self.object.labeled_image
        image.labeled = False
        image.save()
        self.object.delete()
        return HttpResponseRedirect(success_url)

But there is no reason to store whether the image is labeled in a field: you can simply look that up if you want to know this. Indeed, you can add a property:

class Photo(models.Model):
    image = models.ImageField(upload_to='shoes_data/%Y/%m/%d', name='image')
    created = models.DateTimeField(auto_now_add=True)

    @property
    def labeled(self):
        try:
            return self.labeled_image is not None
        except LabeledPhoto.DoesNotExist:
            return False

or annotate the queryset with the fact if a LabeledPhoto exists:

from django.db.models import BooleanField, ExpressionWrapper, Q

Photo.objects.annotate(
    is_labeled=ExpressionWrapper(
        Q(labeled_image__isnull=False),
        output_field=BooleanField()
    )
)