Soft Deletion in Django

Giving your users the ability to delete objects from your database is a risky proposition — some types of objects are low risk, but others, no matter how much you warn them of the risks of deleting things, will lead to customer requests. You know the kind — “So, I deleted this thing, but I didn’t mean to and now I really need it back…can you recover it?” Of course, databases don’t work that way. When a thing is deleted, it’s deleted.

So, the dream: be able to easily define some objects to be soft-deleted and others to be hard-deleted so that your developers don’t have to remember as they are interacting with objects which are which, and be able to easily recover deleted objects for your users when they need you to. Soft deletion can help with this.

The Model

Most objects in Django inherit from models.Model. If we define a SoftDeletionModel that our objects inherit from instead, we can give it whatever attributes we want, and trust that all models that inherit this way will have the same behavior, and we only have to remember it at the time we define the model, not every time we use it. It might look something like this:

class SoftDeletionModel(models.Model):
    deleted_at = models.DateTimeField(blank=True, null=True)

    objects = SoftDeletionManager()
    all_objects = SoftDeletionManager(alive_only=False)

    class Meta:
        abstract = True

    def delete(self):
        self.deleted_at = timezone.now()
        self.save()

    def hard_delete(self):
        super(SoftDeletionModel, self).delete()

The pieces:

• deleted_at: this means that all models inheriting from the SoftDeletionModel will have this attribute available to be set. By default it will be null. I recommend a date instead of a boolean so that you can create a background job that hard-deletes any objects that were “deleted” more than 24 hours/7 days/30 days (whatever the right cadence is for you and your users ) ago — data that users choose to delete should actually be deleted.
• We’ll look at objects and all_objects in the next section. This is what makes this so powerful
• abstract = True: This just means we won’t ever define a SoftDeletionModel object on its own. More detail from the Django docs here.
• The delete method means that whenever you call .delete() on any object that inherits from the SoftDeletionModel, it won’t actually be deleted from the database — its…