#29790: Release notes / Changelog missing information about change in duplicate pk behaviour in 2.1 -------------------------------------+------------------------------------- Reporter: He3lixxx | Owner: nobody Type: Bug | Status: new Component: | Version: 2.1 Documentation | Keywords: multiple primary Severity: Normal | keys migration id uuid Triage Stage: | Has patch: 0 Unreviewed | Needs documentation: 0 | Needs tests: 0 Patch needs improvement: 0 | Easy pickings: 0 UI/UX: 0 | -------------------------------------+------------------------------------- We migrated a model from a AutoField as id (default behaviour) to a UUIDField in the past, using a migration that looked like this with django 2.0: https://code.djangoproject.com/ticket/28541
There was a bug in SQLite though, which as of today only has the workaround listed in the bug tracker: https://code.djangoproject.com/ticket/28541 Thus, we ended up writing our migration like this: https://github.com/fsr- itse/EvaP/blob/master/evap/evaluation/migrations/0062_replace_textanswer_id_with_uuid.py When we try updating to django 2.1 now, this migration fails whenever you call migrate with the error {{{django.db.utils.ProgrammingError: multiple primary keys for table "evaluation_textanswer" are not allowed}}} It works if we add a RemoveField instruction for the old id before setting {{{primary_key=True}}} on the new UUIDField. But this will trigger the SQLite bug listed above. Changing the old AutoField to {{{primary_key=False}}} where the RemoveField instruction would be doesn't fix the error. The documentation states that a object may not have more than one primary key here: https://docs.djangoproject.com/en/2.0/ref/models/fields/#django.db.models.Field.primary_key Still, in the release notes for django 2.1 it should be noted that django's behaviour was changed here. Also, I would appreciate if there was some kind of documentation on how you should migrate primary keys from a field to another if no two primary keys are allowed in between. There should be a way without squashing the migrations as we want to keep the history. -- Ticket URL: <https://code.djangoproject.com/ticket/29790> Django <https://code.djangoproject.com/> The Web framework for perfectionists with deadlines. -- You received this message because you are subscribed to the Google Groups "Django updates" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-updates+unsubscr...@googlegroups.com. To post to this group, send email to django-updates@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-updates/051.719f22fd4d207aab77c393cf72ad54f2%40djangoproject.com. For more options, visit https://groups.google.com/d/optout.