old_contents: # coding=utf-8
  from django.db import models
  
  
  # basic model stuff
  ##########################################
  from django.db.models import Sum
  from django.forms import forms
  from django.utils.datetime_safe import datetime
  
  
  class DataManager(models.Manager):
  
      def get_query_set(self):
          qs = super(DataManager, self).get_query_set()
          return qs.filter(active=True)
          
      def delete(self):
          self.update(active=False)
  
  
  class AllObjectsManager(models.Manager):
  
      def deleted(self):
          return self.filter(active=False)
  
  
  # base model with useful stuff
  class BaseModel(models.Model):
  
      created = models.DateTimeField(auto_now_add=True, editable=False)
      modified = models.DateTimeField(auto_now=True, editable=False)
      deleted = models.DateTimeField(editable=False, null=True)
  
      active = models.BooleanField(default=True, editable=False)
  
      # access only active data objects
      data = DataManager()
      # access all (including deleted) data (active is false)
      objects = AllObjectsManager()
  
      class Meta:
          abstract = True
          ordering = ['-created']
  
      # deleted data is bad - doing it you shouldn't!
      def delete(self, using=None):
          self.active = False
          self.save()
  
      def save(self, force_insert=False, force_update=False, using=None,
               update_fields=None):
  
          if self.active:
              self.deleted = None
          else:
              self.deleted = datetime.now()
  
          super(BaseModel, self).save(force_insert=force_insert, using=using,
                                      update_fields=update_fields)
  
      def reload_me(self):
          if self.id:
              return self.__class__.objects.get(id=self.id)
  
  
  class NamedModel(models.Model):
      name = models.CharField('Name', max_length=150)
  
      class Meta:
          ordering = ['name']
          abstract = True
  
      def __unicode__(self):
          return self.name
  
  
new_contents: # coding=utf-8
  from django.db import models
  from django.db.models.query import QuerySet
  from django.utils.datetime_safe import datetime
  
  # basic model stuff
  ##########################################
  class DataQuerySet(QuerySet):
      def delete(self):
          self.update(active=False, deleted=datetime.now())
  
  
  class AllObjectsQuerySet(QuerySet):
      def undelete(self):
          self.update(active=True, deleted=None)
  
  
  class DataManager(models.Manager):
      use_for_related_fields = True
  
      def get_query_set(self):
          qs = DataQuerySet(self.model, using=self._db)
          return qs.filter(active=True)
  
      def delete(self):
          self.update(active=False, deleted=datetime.now())
  
  
  class AllObjectsManager(models.Manager):
  
      def get_query_set(self):
          return DataQuerySet(self.model, using=self._db)
  
      def deleted(self):
          return self.filter(active=False)
  
  
  # base model with useful stuff
  class BaseModel(models.Model):
  
      created = models.DateTimeField(auto_now_add=True, editable=False, db_index=True)
      modified = models.DateTimeField(auto_now=True, editable=False, db_index=True)
      deleted = models.DateTimeField(editable=False, null=True)
  
      active = models.BooleanField(default=True, editable=False, db_index=True)
  
      # access only active data objects
      data = DataManager()
      # access all (including deleted) data (active is false)
      objects = AllObjectsManager()
  
      class Meta:
          abstract = True
          ordering = ['-created']
  
      # deleted data is bad - doing it you shouldn't!
      def delete(self, using=None):
          self.active = False
          self.save()
  
      def undelete(self, using=None):
          self.active = True
          self.save()
  
      def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
  
          if self.active:
              self.deleted = None
          else:
              self.deleted = datetime.now()
  
          super(BaseModel, self).save(force_insert=force_insert, using=using,
                                      update_fields=update_fields)
  
      def reload_me(self):
          if self.id:
              return self.__class__.objects.get(id=self.id)
  
  
  class NamedModel(BaseModel):
      name = models.CharField('Name', max_length=150, db_index=True)
  
      class Meta:
          ordering = ['name']
          abstract = True
  
      def __unicode__(self):
          return self.name
  
subject: Update models.py