在布尔值上调用成员函数 fetch()

Fatal error: Call to a member function fetch() on boolean in C:xampphtdocsepogeneratormodeldatabase.php on line 34

当我运行此代码时:

    class database
    {
        private $user = 'root';
        private $pass = '';
        public $pdo;

        public function connect() {
            try {
                $this->pdo = new PDO('mysql:host=localhost; dbname=generatordatabase', $this->user, $this->pass);
                echo 'Połączenie nawiązane!';
            }
            catch(PDOException $e) {
                echo 'Połączenie nie mogło zostać utworzone: ' . $e->getMessage();
            }
        }

        public function createTable() {

                        $q = $this->pdo -> query('SELECT * FROM article');
                          while($row = $q->fetch()) {
                              echo $row['id'].' ';
                          }
                          $q->closeCursor();
        }
    }

    ?>

推荐答案

根据 PHP 手册 PDO::查询

PDO::query() 返回一个 PDOStatement 对象，或者失败时返回 FALSE.