[Bug] Transient object cascading deletion fails after v1.7.0

[manning-ncsa]

After migrating from MariaDB to PostgreSQL in v1.7.0, Transient objects can no longer be deleted in the expected way, using for example Transient.objects.get(name='2021abcd').delete(), because the cascading deletion of associated objects (Cutout, Aperture, SEDFittingResult, etc) does not occur. Instead, errors like the following are shown:

django.db.utils.IntegrityError: update or delete on table "host_cutout" violates foreign key constraint "host_aperture_cutout_id_13ce5cd4_fk_host_cutout_id" on table "host_aperture"
DETAIL:  Key (id)=(1220837) is still referenced from table "host_aperture".

Until a correction to the database is devised, a workaround is to manually remove these objects using clunky code like this:

print(f'''Deleting transient "{transient.name}"...''')
objs = StarFormationHistoryResult.objects.filter(transient__name=transient.name)
for obj in objs:
    print(f'''{obj}''')
    obj.delete()
objs = SEDFittingResult.objects.filter(transient__name=transient.name)
for obj in objs:
    print(f'''{obj.model_file}''')
    obj.delete()
objs = Aperture.objects.filter(transient__name=transient.name)
for obj in objs:
    print(f'''{obj.name}''')
    obj.delete()
objs = Cutout.objects.filter(transient__name=transient.name)
for obj in objs:
    print(f'''{obj.name}''')
    obj.delete()
transient.delete()