public function optimize()
    {
        $mappers = $this->mappers;
        
        $this->assignPrimaryKey($mappers)
             ->assignPrimaryTitle($mappers);

        foreach ($mappers as $mapper) {
            $optimizer = new FieldOptimizer($mapper->field, $mapper->meta);

            $this->addField($optimizer->optimize()->getField());
        }

        return $this;
    }