Yet another approach to provide soft (logical) delete or masking (thrashing) django models instead of deleting them physically from db.
To create a non-deletable model just inherit it from
class MyModel(PermanentModel): pass
It automatically changes delete behaviour to hide objects instead of deleting them:
>>> a = MyModel.objects.create(pk=1) >>> b = MyModel.objects.create(pk=2) >>> MyModel.objects.count() 2 >>> a.delete() >>> MyModel.objects.count() 1
To recover a deleted object just call its
>>> a.restore() >>> MyModel.objects.count() 2
force kwarg to enforce physical deletion:
>>> a.delete(force=True) # Will act as the default django delete >>> MyModel._base_manager.count() 0
If you need to restore a deleted object instead of re-creating the same one use the
class MyModel(PermanentModel): class Permanent: restore_on_create = True
In this case
QuerySet provides check existence of same attribute objects and restores them if they've been deleted, creating new ones if not.
It changes the default model manager to ignore deleted objects, adding a
deleted_objects manager to see them instead:
>>> MyModel.objects.count() 2 >>> a.delete() >>> MyModel.objects.count() 1 >>> MyModel.deleted_objects.count() 1 >>> MyModel.all_objects.count() 2 >>> MyModel._base_manager.count() 2
QuerySet.delete method will act as the default django delete, with one exception - objects of models subclassing
PermanentModel will be marked as deleted; the rest will be deleted physically:
You can still force django query set physical deletion:
Using custom querysets
Inherit your query set from
class ServerFileQuerySet(PermanentQuerySet) pass
DeletedQuerySetin you model manager declaration:
class MyModel(PermanentModel) objects = MultiPassThroughManager(ServerFileQuerySet, NonDeletedQuerySet) deleted_objects = MultiPassThroughManager(ServerFileQuerySet, DeletedQuerySet) all_objects = MultiPassThroughManager(ServerFileQuerySet, PermanentQuerySet)
- Check for existence of the object.
- Restore it if it was deleted.
- Create a new one, if it was never created.
The default field named is 'removed', but you can override it with the PERMANENT_FIELD variable in settings.py:
PERMANENT_FIELD = 'deleted'
- Django 1.7+
- Python 2.7, 3.4+