Doctrine turns given value into null - php

Question

I've got a problem that looks kinda hard to describe, but i'm gonna try anyway.
In my MatchesResultscontroller, i've got the following code, to build up an entity:
$em = $this->getServiceLocator()->get('Doctrine\ORM\EntityManager');
if($this->getRequest()->isPost()) {
// get id of current match
$match_id = (int)$this->params()->fromRoute('match', 1);
// find match based on current match id
$results = $em->getRepository('Competitions\Entity\MatchesResults')->findBy(
['match_id' => $match_id]
);
$matchresults = new \Competitions\Entity\MatchesResults();
// Input
$matchresults->stek = $this->getRequest()->getPost('Res_Stek');
$matchresults->member_id = $this->getRequest()->getPost('Res_Name');
$matchresults->weight = $this->getRequest()->getPost('Res_Gewicht');
$matchresults->points = $this->getRequest()->getPost('Res_Punten');
$matchresults->match_id = $match_id;
$matchresults->amount = $this->getRequest()->getPost('Res_Aantal');
// Add
$em->persist($matchresults);
$em->flush($matchresults);
// Redirect back to the competition overview
return $this->redirect()->toRoute('admin-match');
The file MatchesResults.php looks like this
<?php
namespace Competitions\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
#ORM\Table()
#ORM\Entity
#ORM\Table(name="matches_results")
*/
class MatchesResults {
/**
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
* #ORM\Column(type="integer")
*/
public $id;
/** #ORM\Column(type="integer") */
public $match_id;
/** #ORM\Column(type="integer") */
public $member_id;
/** #ORM\Column(type="integer") */
public $stek;
/** #ORM\Column(type="integer") */
public $weight;
/** #ORM\Column(type="integer") */
public $amount;
/** #ORM\Column(type="float") */
public $points;
/** #ORM\Column(type="integer") */
public $position;
public $var;
/**
* #ORM\OneToMany(targetEntity="Competitions\Entity\Matches", mappedBy="Members")
* #ORM\JoinColumn(name="match_id", referencedColumnName="id")
*/
public $result;
public function getResult() {
return $this->result;
}
/**
* #ORM\OneToOne(targetEntity="Members\Entity\Members")
* #ORM\JoinColumn(name="member_id", referencedColumnName="user_id") <----- problem here
*/
public $member;
public function getMember() {
return $this->member;
}
}
When i need to get an overview of all results of a given match, with the correct user linked to that result, it works perfectly.
However, when i need to add a new result, I get a member_id = null, since doctrine is trying to get the member_id of a non existing result.
$matchresults->stek = $this->getRequest()->getPost('Res_Stek');
$matchresults->member_id = $this->getRequest()->getPost('Res_Name');
$matchresults->weight = $this->getRequest()->getPost('Res_Gewicht');
$matchresults->points = $this->getRequest()->getPost('Res_Punten');
$matchresults->match_id = $match_id;
$matchresults->amount = $this->getRequest()->getPost('Res_Aantal');
This code does set all values correctly into the entity, but the entities member_id field is just overwritten.
How would i solve this issue?
I could make a separate file that does not contain the troubling line, but i don't think that is a very elegant solution.
Mark