subqueries.py 文件源码

def add_update_values(self, values):
        """
        Convert a dictionary of field name to value mappings into an update
        query. This is the entry point for the public update() method on
        querysets.
        """
        values_seq = []
        for name, val in six.iteritems(values):
            field = self.get_meta().get_field(name)
            direct = not (field.auto_created and not field.concrete) or not field.concrete
            model = field.model._meta.concrete_model
            if not direct or (field.is_relation and field.many_to_many):
                raise FieldError(
                    'Cannot update model field %r (only non-relations and '
                    'foreign keys permitted).' % field
                )
            if model is not self.get_meta().model:
                self.add_related_update(model, field, val)
                continue
            values_seq.append((field, model, val))
        return self.add_update_fields(values_seq)