private function applyPrimaryKey(PropertyField $field, IdProperty $prop)
    {
        unset($prop);

        $model  = $this->targetModel();
        $source = $model->source();

        $sql = strtr(
            'ALTER TABLE `%table` ADD PRIMARY KEY (`%key`)',
            [
                '%table' => $source->table(),
                '%key'   => $field->ident(),
            ]
        );
        $source->db()->query($sql);

        return $this;
    }