public function fetchData()
 {
     if ($this['host_id']) {
         $host = new LernmarktplatzHost($this['host_id']);
         if ($host) {
             $data = $host->fetchItemData($this['foreign_material_id']);
             if (!$data) {
                 return false;
             }
             if ($data['deleted']) {
                 return "deleted";
             }
             //user:
             $user = LernmarktplatzUser::findOneBySQL("foreign_user_id", array($data['user']['user_id'], $host->getId()));
             if (!$user) {
                 $user = new LernmarktplatzUser();
                 $user['foreign_user_id'] = $data['user']['user_id'];
                 $user['host_id'] = $host->getId();
             }
             $user['name'] = $data['user']['name'];
             $user['avatar'] = $data['user']['avatar'] ?: null;
             $user['description'] = $data['user']['description'] ?: null;
             $user->store();
             //material:
             $material_data = $data['data'];
             unset($material_data['material_id']);
             unset($material_data['user_id']);
             unset($material_data['mkdate']);
             $this->setData($material_data);
             $this->store();
             //topics:
             $this->setTopics($data['topics']);
             foreach ((array) $data['reviews'] as $review_data) {
                 $currenthost = LernmarktplatzHost::findOneByUrl(trim($review_data['host']['url']));
                 if (!$currenthost) {
                     $currenthost = new LernmarktplatzHost();
                     $currenthost['url'] = trim($review_data['host']['url']);
                     $currenthost['last_updated'] = time();
                     $currenthost->fetchPublicKey();
                     if ($currenthost['public_key']) {
                         $currenthost->store();
                     }
                 }
                 if ($currenthost && $currenthost['public_key'] && !$currenthost->isMe()) {
                     $review = LernmarktplatzReview::findOneBySQL("foreign_review_id = ? AND host_id = ?", array($review_data['foreign_review_id'], $currenthost->getId()));
                     if (!$review) {
                         $review = new LernmarktplatzReview();
                         $review['foreign_review_id'] = $review_data['foreign_review_id'];
                         $review['material_id'] = $this->getId();
                         $review['host_id'] = $currenthost->getId();
                     }
                     $review['review'] = $review_data['review'];
                     $review['rating'] = $review_data['rating'];
                     if ($review_data['chdate']) {
                         $review['chdate'] = $review_data['chdate'];
                     }
                     if ($review_data['mkdate']) {
                         $review['mkdate'] = $review_data['mkdate'];
                     }
                     $user = LernmarktplatzUser::findOneBySQL("foreign_user_id", array($review_data['user']['user_id'], $currenthost->getId()));
                     if (!$user) {
                         $user = new LernmarktplatzUser();
                         $user['foreign_user_id'] = $review_data['user']['user_id'];
                         $user['host_id'] = $currenthost->getId();
                     }
                     $user['name'] = $review_data['user']['name'];
                     $user['avatar'] = $review_data['user']['avatar'] ?: null;
                     $user['description'] = $review_data['user']['description'] ?: null;
                     $user->store();
                     $review['user_id'] = $user->getId();
                     $review->store();
                 }
             }
         }
     }
     return true;
 }