Re: Django Postgres Intermediary doesn't set ON DELETE CASCADE

Indeed! I have actually used the admin site to do it before I posted this it's just something I didn't know was by design. After numerous searches I came here but I may have been asking the wrong questions in google :). 

The shell would be good if I have quite a few I need to delete. Thankfully I had only one entry.

Thanks for help, Jason.

On Saturday, 23 June 2018 14:46:44 UTC+1, Jason wrote:

well, nothing stopping you from doing the same in the django shell and doing `Group.objects.get(pk = some_pk).delete`.  that would be an alternative for going straight to the db.

I can see some issues with this coming up, especially if you're doing deletes with django's raw sql capability.  But that should never happen, you should do a select then iterate and delete.

On Saturday, June 23, 2018 at 9:28:15 AM UTC-4, James Bellaby wrote:

OK. So it's by design.

So during development I can't go straight to the database and delete a "Group" quickly due to an error I made. I'd have to set up tests to deal with it at an application level.

No probs though. I'm just happy I know it can't be done and not that it's a bug I'd have to wait for.

Thanks for the answers :)

On Saturday, 23 June 2018 14:16:33 UTC+1, Melvyn Sopacua wrote:

On zaterdag 23 juni 2018 14:40:30 CEST Jason wrote:
> Not quite.  If you run python manage.py sqlmigrate <appname>
> <migration_name>, you can see the SQL generated for that migration.
>
> https://docs.djangoproject.com/en/2.0/ref/django-admin/#django-admin-sqlmigr
> ate
>
> Because Django emulates Cascade, its done outside of the db, and therefore
> shouldn't be a db-level constraint.

The case for and against can be made pretty much with the same argument:
- for: if a row is deleted outside of Django, so by direct database
manipulation, then the relations become inconsistent, so having database
reflect models prevents this.
- against: if a row is deleted outside of Django, so by direct database
manipulation, then signals are not processed and objects are deleted
regardless. The consequences of this are unpredictable and application
specific.

Django chose to not align model relations with database representation.
Knowing this means you have to handle things through Django exclusively where
it matters.

--
Melvyn Sopacua

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscribe@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/00e2d392-99d5-43a6-b6f7-65f348b2185c%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.