def _save_table(self, raw=False, cls=None, force_insert=False,
force_update=False, using=None, update_fields=None):
"""
Does the heavy-lifting involved in saving. Updates or inserts the data
for a single table.
"""
meta = cls._meta
non_pks = [f for f in meta.local_concrete_fields if not f.primary_key]
if update_fields:
non_pks = [f for f in non_pks
if f.name in update_fields or f.attname in update_fields]
pk_val = self._get_pk_val(meta)
if pk_val is None:
pk_val = meta.pk.get_pk_value_on_save(self)
setattr(self, meta.pk.attname, pk_val)
pk_set = pk_val is not None
if not pk_set and (force_update or update_fields):
raise ValueError("Cannot force an update in save() with no primary key.")
updated = False
# If possible, try an UPDATE. If that doesn't update anything, do an INSERT.
if pk_set and not force_insert:
base_qs = cls._base_manager.using(using)
values = [(f, None, (getattr(self, f.attname) if raw else f.pre_save(self, False)))
for f in non_pks]
forced_update = update_fields or force_update
updated = self._do_update(base_qs, using, pk_val, values, update_fields,
forced_update)
if force_update and not updated:
raise DatabaseError("Forced update did not affect any rows.")
if update_fields and not updated:
raise DatabaseError("Save with update_fields did not affect any rows.")
if not updated:
if meta.order_with_respect_to:
# If this is a model with an order_with_respect_to
# autopopulate the _order field
field = meta.order_with_respect_to
filter_args = field.get_filter_kwargs_for_object(self)
order_value = cls._base_manager.using(using).filter(**filter_args).count()
self._order = order_value
fields = meta.local_concrete_fields
if not pk_set:
fields = [f for f in fields if not isinstance(f, AutoField)]
update_pk = bool(meta.has_auto_field and not pk_set)
result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
if update_pk:
setattr(self, meta.pk.attname, result)
return updated
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