      event = models.OneToOneField(Event, verbose_name='awesome event')
  
  
  class Guest(models.Model):
      event = models.OneToOneField(Event)
      name = models.CharField(max_length=255)
  
      class Meta:
          verbose_name = "awesome guest"
  
 
</s> remove     event = models.OneToOneField(Event, verbose_name='awesome event')
 </s> add     event = models.OneToOneField(Event, models.CASCADE, verbose_name='awesome event') </s> remove     event = models.ForeignKey(Event, on_delete=models.DO_NOTHING)
 </s> add     event = models.ForeignKey(Event, models.DO_NOTHING) </s> remove     parent = models.ForeignKey(UUIDPKParent)
 </s> add     parent = models.ForeignKey(UUIDPKParent, models.CASCADE) </s> remove     owner = models.ForeignKey('Person', null=True)
    main_room = models.OneToOneField('Room', related_name='main_room_of', null=True)
 </s> add     owner = models.ForeignKey('Person', models.SET_NULL, null=True)
    main_room = models.OneToOneField('Room', models.SET_NULL, related_name='main_room_of', null=True) </s> remove     parent = models.ForeignKey(UUIDPKParent)
 </s> add     parent = models.ForeignKey(UUIDPKParent, models.CASCADE)
    event = models.OneToOneField(Event, models.CASCADE)
      event = models.OneToOneField(Event, verbose_name='awesome event')
  
  
  class Guest(models.Model):
    event = models.OneToOneField(Event, models.CASCADE)
      name = models.CharField(max_length=255)
  
      class Meta:
          verbose_name = "awesome guest"
  
keep keep keep keep replace keep keep keep keep keep
 Fixed #21127 -- Started deprecation toward requiring on_delete for ForeignKey/OneToOneField 
tests/admin_utils/models.py