sql - Why can't I delete a model instance with related objects? -

I'm trying to delete a user object in a Django app, but I When deleting users , IntegrityError in a related object. Related object looks like this:

  class follow (models.model): source = models.ForeignKey (user, related_name = 'unfollowings_by') target = models.ForeignKey (user, related_name = ' Unfollowings_of ') created_on = models.DateTimeField (auto_now_add = true)   
 but when deleting a  user , I receive an error like the following:  
 
 IntegrityError: Update or Delete "auth_user" foreign key barrier on table "source_id_refs_id_5b69e09fc6161c2a" "core_unfollowing" on the table violates the description:. Key (id) = (6439) is still referenced from the table "core_unfollowing"   
 What is the deal? Associated  user  has been removed, then unfollowing related   items should not be automatically removed? For what it's worth, I added a clear  on_delete = models.CASCADE  for both  Unfollowing.source  and  Unfollowing.target  (even if it is worth it That's the default) and I still get the same error   
 
 
 It's really awkward. Here are some things I'll try:  
 First of all, did you update the database schema after adding  on_delete = models.CASCADE . If not, then there will be no effect on this. You can double check that CASCADE removed  dashing database schema directly from Django, by not detecting it.  
 I think there is more to a database engine related error than this of Django. If you are 100% positive  delete on CASCADE, then  auth_user is active in the table and related tables, then you can try to delete a user directly from your SQL client. If this works, and the same user bothers you with Django (or a similar user, given the fact that you have erased one earlier), try dumping the SQL query that Django is doing And repeat it with your SQL client.  
 This is the way that I will take. Also, check whether it is with a specific user or every user, check the reference hanging in the unfollowing table. There may also be an old table that is used and it is giving you problems.  
 I will focus directly on the research with the database and a SQL client and after that I have been able to work it out there,  
 I hope it can help a little bit. .  
  
 / P> 
 Good luck!