对MySQL的查询返回null，在它以前工作得很好

基本上，我想使用php-PDO创建一个查询，以检查表"page"是否存在于我的数据库"test"中。我不知道怎么做，我在这里得到了一些帮助。

我的代码运行得很完美。。。直到现在，我在课堂上一切顺利。。。现在CCD_ 1返回CCD_。除了把这个放到OOP中，我什么都没改。。。

有人能发现问题吗？？因为我看不见。Thx u

$r1 = $this->db->query('SHOW TABLES LIKE ''page''');

 // Debbug
    $r2 = $r1->fetchAll;
    var_dump ($r2);
    if (count($r1->fetchAll()) > 0 ) {
        echo "The table PAGE exists";
    }

完整的类别是以下一个

    class phase2 {
        function __construct () {
        $dbFile = 'dbconfig.php';
        $this->dbFile = $dbFile;
        require_once ("$dbFile");   

        $step = $_GET["step"];
        $username = $DB_USER;
        $password = $DB_PASS;
        $server = $DB_SERVER;
        $dbName = $DB_NAME;
        $this->step = $step;
        $this->dbFile = $dbFile;
        $this->username = $username;
        $this->password = $password;
        $this->server = $server;
        $this->dbName = $dbName;
        $db = new PDO ('mysql:host=' .$server.';dbname='.$this->dbName,$this->username,$this->password);
        $this->db = $db;
        if (empty ($_GET['fot']) ) { 
            $fOT = 'false'; 
        } elseif ($_GET['true']) { $fOT = 'true'; }
        $this->fOT = $fOT;
        $this->IDB = $this->handleDatabase( 1 );
        $this->IDB2 = $this->handleDatabase( 2 );
        $this->IDB3 = $this->handleDatabase( 3 );
        }

public function handleDatabase ($num = 1){
// Prepare SQL Statements
    $IDB1 = $this->db->prepare( 
         "CREATE TABLE pages (
          id int(11) NOT NULL auto_increment,
         subject_id int(11) NOT NULL,
          menu_name varchar(30) NOT NULL,
          position int(3) NOT NULL,
          visible tinyint(1) NOT NULL,
          content text NOT NULL,
          PRIMARY KEY  (id)
    )ENGINE=MyISAM AUTO_INCREMENT=7 DEFAULT CHARSET=utf8");
    $IDB2 = $this->db->prepare("
        CREATE TABLE subjects (
          id int(11) NOT NULL auto_increment,
          menu_name varchar(30) NOT NULL,
          position int(3) NOT NULL,
          visible tinyint(1) NOT NULL,
          PRIMARY KEY  (id)
    )ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=utf8");
    $IDB3 = $this->db->prepare("
        CREATE TABLE users (
          id int(11) NOT NULL auto_increment,
          username varchar(50) NOT NULL,
          hashed_password varchar(40) NOT NULL,
          PRIMARY KEY  (id)
    )ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=utf8");
    $name = "IDB".$num;
    return isset( $$name)?$$name:false;
}
//Set Option to True or False
function createTablePages ($fOT){

    $r1 = $this->db->query('SHOW TABLES LIKE ''page''');
// Debbug
    $r2 = $r1->fetchAll;
    var_dump ($r2);

    if (count($r1->fetchAll()) > 0) {

        echo "The table PAGE exists";
    } elseif ($fOT == 'true') {
            echo "enteres";
            $this->IDB1->execute();
            $this->stepFunction (1,false);
    } 
}
function createTableSubjects ($fOT){
    $r2 = $this->db->query('SHOW TABLES LIKE ''subjects''');
    if (count($r2->fetchAll()) > 0  && $fOT == 'false') {
            echo "The table SUBJECTS exists ";
    } elseif ($fOT == 'true') {
        $this->IDB2->execute();
        $this->stepFunction (2,false);
    }
}
function createTableUsers ($fOT){
    $r3 = $this->db->query('SHOW TABLES LIKE ''users''');   
    if (count($r3->fetchAll()) > 0  && $fOT == 'false') {
            echo "The table USERS exists";
    } elseif ($fOT == 'true') {
            $this->IDB3->execute();
            echo "Would you like to populate all the tables?";
    }   
}

public function stepFunction ($fOT,$step){
switch ($step) {
    case 0: 
            $this->createTablePages ($fOT);
            break;
    case 1: 
            $this->createTableSubjects($fOT);
            break;
    case 2: $this->createTableUsers ($fOT);
            break;
    }

}
    }