Re: Django Logical Deletes on Models

[Peter of the Norse]

Steal code from the current Model.delete method.  It uses django.db.models.deletion.Collector to find the associated objects.  I would extend that to do what you want.

On Aug 4, 2015, at 7:38 AM, psychok7 <nun...@gmail.com> wrote:

So i decided to fork pinax-models because i need the capability of soft deleting objects and their related (setting a flag but not really deleting them). This is a project that seems to be unmaintained , so i diged into the code and i am trying to make some improvements.

It basically fetched the objects, looks for its related and then saves the date_removed to fake the deletion.

It still has some issues and one of them which i am trying to solve is that it always "cascades" the deletes of the related but it should only do it if the related field is not nullable. if its nullable then it should not delete the related field.

I have 2 question regarding this matter ( i  am using Django 1.7):

1- How can i improve this code below to support that feature? I know it has something to do with _meta, thought about using `obj._meta.get_fields_with_model` but i am afraid it does not do `options.concrete_fields + options.many_to_many + options.virtual_fields`. i was thinking about getting  all the existing fields in a model an then evaluate if its a foreign key to a certain model class and then check if `obj._meta.get_field('something').null`. Is this the right approach??

2 - The original author is using self._meta.get_all_related_objects() but in the _metadocumentation i saw other functions like for example get_all_related_many_to_many_objectsso do i need to add that validation to the code as well or self._meta.get_all_related_objects() is enough ??

I am trying to improve this and push it to my pinax-models fork so any help would be appreciated.

code:

class CustomLogicalDeleteModel(LogicalDeleteModel):

    def delete(self):
        # Fetch related models
        related_objs = [
            relation.get_accessor_name()
            for relation in self._meta.get_all_related_objects()
        ]

        for objs_model in related_objs:

            if hasattr(self, objs_model):
                local_objs_model = getattr(self, objs_model)
                if hasattr(local_objs_model, 'all'):
                    # Retrieve all related objects
                    objs = local_objs_model.all()

                    for obj in objs:
                        # Checking if inherits from logicaldelete
                        if not issubclass(obj.__class__, LogicalDeleteModel):
                            break
                        obj.delete()
                else:
                    obj = local_objs_model

                    if not issubclass(obj.__class__, LogicalDeleteModel):
                        break
                    obj.delete()

        # Soft delete the object
        self.date_removed = datetime.datetime.now()
        self.save()

    class Meta:
        abstract = True

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Peter of the Norse

Rahm...@Radio1190.org