Making Orm.save() more robust

[Jaymon]

We have a version of save that's like this:

    def save(self):
        try:
            super(Orm, self).save()

        except UniqueError as e:
            pk_name = self.schema.pk_name
            if pk_name and (pk_name in self.modified_fields):
                self.update()

            else:
                raise

It would be great to have a more robust version, that catches the unique error, pulls out the fields, then sets those fields in a where portion of a Query and tries the update.

[Jaymon]

I think this is no longer needed since there is now Orm.upsert