      title = models.CharField(max_length=50)
  
  
  class NamedURL(models.Model):
      title = models.ForeignKey(Title, related_name='attached_%(app_label)s_%(class)s_set')
      url = models.URLField()
  
      class Meta:
          abstract = True
  
 
</s> remove     post = models.ForeignKey("Post")
 </s> add     post = models.ForeignKey("Post", models.CASCADE) </s> remove     title = models.ForeignKey(Title)
 </s> add     title = models.ForeignKey(Title, models.CASCADE) </s> remove     item = models.ForeignKey(Item)
 </s> add     item = models.ForeignKey(Item, models.CASCADE) </s> remove     post = models.ForeignKey(Post, related_name='attached_%(class)s_set')
 </s> add     post = models.ForeignKey(Post, models.CASCADE, related_name='attached_%(class)s_set') </s> remove     parent = models.OneToOneField(Place, parent_link=True)
 </s> add     parent = models.OneToOneField(Place, models.CASCADE, parent_link=True)
    title = models.ForeignKey(Title, models.CASCADE, related_name='attached_%(app_label)s_%(class)s_set')
      title = models.CharField(max_length=50)
  
  
  class NamedURL(models.Model):
    title = models.ForeignKey(Title, models.CASCADE, related_name='attached_%(app_label)s_%(class)s_set')
      url = models.URLField()
  
      class Meta:
          abstract = True
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/model_inheritance/models.py