php - Symfony2 Form ManyToOne Entity-Type -

this entity:

class myentity {     /**      * @var \otherentity      *      * @orm\manytoone(targetentity="otherentity")      * @orm\joincolumns({      *   @orm\joincolumn(name="otherentity_id", referencedcolumnname="id")      * })      */     private $otherentity;     // other fields } 

my controller's action:

someaction(request $request) {     $em = $this->getdoctrine()->getentitymanager();     // simplified step here id=5, entities of class myentity link otherentity id=5      $otherentity = $this->getdoctrine()->getrepository('mytestbundle:otherentity')->find(5);      $myentity = new myentity();     $myentity->setotherentity($otherentity);      $form = $this->createform(new myentitytype(), $myentity);     // form stuff isvalid, ismethod('post') etc. } 

this formtype:

class myentitytype extends abstracttype {     public function buildform(formbuilderinterface $builder, array $options) {         parent::buildform($builder, $options);         $builder->add('name', 'text');         // how add entity join added myentity otherentity (with id=5)?        // tried this:        ->add('otherentity', 'entity',            array('class' => 'my\mytestbundle\entity\otherentity',                   'read_only' => true,                   'property' => 'id',                   'query_builder' => function (                 \doctrine\orm\entityrepository $repository) {                return $repository->createquerybuilder('o')                            ->where('o.id = ?1')                        ->setparameter(1, 5);     } ) 

) // ... other fields } // standard formtype methods etc. }

so question is, have choose $builder->add adding otherentity, if $em->persist($myentity) inside controller persist added myentity through form, have record in database:

id | name   | otherentity_id 1  | 'test' | 5 

note: don't want persist new otherentity, want create new myentity , add foreign-key of otherentity.

can't use entity form type this:

$builder->add('otherentity', 'entity', array(     'class' => 'mytestbundle:otherentity' ));