Method presort_saves

lib/sqlalchemy/orm/dependency.py:1052–1084

(self, uowcommit, states)

                )

    def presort_saves(self, uowcommit, states):
        if not self.passive_updates:
            # if no passive updates, load history on
            # each collection where parent has changed PK,
            # so that prop_has_changes() returns True
            for state in states:
                if self._pks_changed(uowcommit, state):
                    uowcommit.get_attribute_history(
                        state, self.key, attributes.PASSIVE_OFF
                    )

        if not self.cascade.delete_orphan:
            return

        # check for child items removed from the collection
        # if delete_orphan check is turned on.
        for state in states:
            history = uowcommit.get_attribute_history(
                state, self.key, attributes.PASSIVE_NO_INITIALIZE
            )
            if history:
                for child in history.deleted:
                    if self.hasparent(child) is False:
                        uowcommit.register_object(
                            child,
                            isdelete=True,
                            operation="delete",
                            prop=self.prop,
                        )
                        for c, m, st_, dct_ in self.mapper.cascade_iterator(
                            "delete", child
                        ):
                            uowcommit.register_object(st_, isdelete=True)

    def process_deletes(self, uowcommit, states):
        secondary_delete = []