在Doctrine中直接查询没有模型的mongodb集合

Question

I have this code which will query data to a MongoDB Collection:

namespace RemoteStaff\Mongo\Resources;
use RemoteStaff\AbstractMongoResource;
use RemoteStaff\Documents\CandidateAsl;
use RemoteStaff\Documents\LanguageObject;

class CandidateAslResource extends AbstractMongoResource
{
   public function saveCandidateAsl($params){

    $dm = $this->getDocumentManager();
    $marlon = $dm->getRepository('RemoteStaff\Documents\CandidateAsl')->findOneBy(["nationality"=>"223756"]);
    print_r($marlon);
   }
}

How do I query directly to a mongo collection without a model like RemoteStaff\Documents\CandidateAsl ?

The reason I want to do this is because I will do the model later on, as for now I just need to query to a mongo collection, get result without making a document model.

I tried looking http://docs.doctrine-project.org/projects/doctrine-mongodb-odm but seems I cant find what I need. So basically I need a query something like this I think:

$marlon = $dm->getRepository('my_mongodb_collection_name')->findOneBy(["nationality"=>"223756"]);