          ordering = ['id']
  
  
  class BookWithYear(Book):
      book = models.OneToOneField(Book, parent_link=True)
      published_year = models.IntegerField()
      aged_authors = models.ManyToManyField(
          AuthorWithAge, related_name='books_with_year')
  
  
 
</s> remove     author = models.OneToOneField(Author, parent_link=True)
 </s> add     author = models.OneToOneField(Author, models.CASCADE, parent_link=True) </s> remove     book = models.ForeignKey(BookWithYear)
 </s> add     book = models.ForeignKey(BookWithYear, models.CASCADE) </s> remove     author = models.OneToOneField(Author)
 </s> add     author = models.OneToOneField(Author, models.CASCADE) </s> remove     author = models.ForeignKey(Author, to_field='name', related_name='i_like')
    likes_author = models.ForeignKey(Author, to_field='name', related_name='likes_me')
 </s> add     author = models.ForeignKey(Author, models.CASCADE, to_field='name', related_name='i_like')
    likes_author = models.ForeignKey(Author, models.CASCADE, to_field='name', related_name='likes_me') </s> remove     media = models.OneToOneField(Media, primary_key=True, parent_link=True)
 </s> add     media = models.OneToOneField(Media, models.CASCADE, primary_key=True, parent_link=True)
    book = models.OneToOneField(Book, models.CASCADE, parent_link=True)
          ordering = ['id']
  
  
  class BookWithYear(Book):
    book = models.OneToOneField(Book, models.CASCADE, parent_link=True)
      published_year = models.IntegerField()
      aged_authors = models.ManyToManyField(
          AuthorWithAge, related_name='books_with_year')
  
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/prefetch_related/models.py