Migrate Django model to unique_together constraint
If you are happy to choose one of the duplicates arbitrarily, I think the following might do the trick. Perhaps not the most efficient but simple enough and I guess you only need to run this once. Please verify this all works yourself on some test data in case I've done something silly, since you are about to delete a bunch of data.
First we find groups of objects which form duplicates. For each group, (arbitrarily) pick a "master" that we are going to keep. Our chosen method is to pick the one with lowest pk
from django.db.models import Min, Countmaster_pks = MyModel.objects.values('A', 'B', 'C' ).annotate(Min('pk'), count=Count('pk') ).filter(count__gt=1 ).values_list('pk__min', flat=True)we then loop over each master, and delete all its duplicates
masters = MyModel.objects.in_bulk( list(master_pks) )for master in masters.values(): MyModel.objects.filter(a=master.a, b=master.b, c=master.c ).exclude(pk=master.pk).del_ACCIDENT_PREVENTION_ete()