public function getPointsByChallengeId($challengeId)
 {
     $sql = "SELECT pointID, challangeID, date, weight FROM weighpoints WHERE challangeID = :challengeId";
     //        $sql = "select pointID, challangeID, date, weight from weighpoints";
     $dbh = new PDO(DBConfig::$DB_CONNSTRING, DBConfig::$DB_USERNAME, DBConfig::$DB_PASSWORD);
     $stmt = $dbh->prepare($sql);
     $stmt->execute(array(':challengeId' => $challengeId));
     $resultList = $stmt->fetchAll(PDO::FETCH_ASSOC);
     //        $resultSet = $dbh->query($sql);
     var_dump($resultList);
     $lijst = array();
     foreach ($resultList as $rij) {
         $challengeDAO = new ChallengeDAO();
         $challenge = $challengeDAO->getById($rij["challangeID"]);
         $weighpoint = Weighpoint::create($rij["pointID"], $challenge, $rij["weight"], $rij["date"]);
         var_dump($weighpoint);
         array_push($lijst, $weighpoint);
     }
     $dbh = null;
     return $lijst;
 }
    <body>
        <?php 
//        var_dump($userLijst);
print "<pre>";
print_r($userLijst);
print "</pre>";
//        var_dump($challengeLijst);
print "<pre>";
print_r($challengeLijst);
print "</pre>";
foreach ($challengeLijst as $challenge) {
    $username = $challenge->getUser()->getUsername();
    print $username;
}
$challengeDAO = new ChallengeDAO();
$challenge = $challengeDAO->getById(1);
//        var_dump($challenge);
print "<pre>";
print_r($challenge);
print "</pre>";
//        var_dump($weighpointLijst);
print "<pre>";
print_r($weighpointLijst);
print "</pre>";
foreach ($weighpointLijst as $weighpoint) {
    $challengeId = $weighpoint->getChallenge()->getChallengeId();
    echo $challengeId . "</br>";
}
print "<pre>";
print_r($viewerLijst);
print "</pre>";