Fatal error: Uncaught TypeError: Argument 1 passed to SqlUtil::transformToBoolean() must be of the type string, null given, called in /var/www/web282/html/bontaro/class/dao/ArticleDao.php on line 89 and defined in /var/www/web282/html/bontaro/class/util/SqlUtil.php:5 Stack trace: #0 /var/www/web282/html/bontaro/class/dao/ArticleDao.php(89): SqlUtil->transformToBoolean(NULL) #1 /var/www/web282/html/bontaro/class/Article.php(62): ArticleDao->getArticle('schluesselanhae...') #2 /var/www/web282/html/bontaro/index.php(36): Article->__construct('schluesselanhae...', Object(mysqli)) #3 {main} thrown in /var/www/web282/html/bontaro/class/util/SqlUtil.php on line 5