我是PHP和PDO的新手，我正在按照教程试图学习，我怎么会收到以下错误。如果有人可以帮助我或给我一些提示，我们将不胜感激。
致命错误：在第41行的dbConnect.php中调用非对象的成员函数prepare（）。
这是dbConnect.php：
<?PHP
class Database{
private $host = DB_HOST;
private $user = DB_USER;
private $pass = DB_PASS;
private $dbname = DB_NAME;
private $dbh;
private $error;
private $stmt;
public function __construct(){
// Set DSN
$dsn = 'mysql:host=' . $this->host . ';dbname=' . $this->dbname;
// Set options
$options = array(
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
);
// Create a new PDO instanace
try{
$this->dbh = new PDO('$dsn, $this->user, $this->pass, $options');
}
// Catch any errors
catch(PDOException $e){
$this->error = $e->getMessage();
}
}
public function query($query){
$this->stmt = $this->dbh->prepare($query);
}
public function bind($param, $value, $type = null){
if (is_null($type)) {
switch (true) {
case is_int($value):
$type = PDO::PARAM_INT;
break;
case is_bool($value):
$type = PDO::PARAM_BOOL;
break;
case is_null($value):
$type = PDO::PARAM_NULL;
break;
default:
$type = PDO::PARAM_STR;
}
$this->stmt->bindValue($param, $value, $type);
}
}
public function execute(){
return $this->stmt->execute();
}
public function resultset(){
$this->execute();
return $this->stmt->fetchAll(PDO::FETCH_ASSOC);
}
public function single(){
$this->execute();
return $this->stmt->fetch(PDO::FETCH_ASSOC);
}
public function rowCount(){
return $this->stmt->rowCount();
}
// Return last inserted id as string
public function lastInsertId(){
return $this->dbh->lastInsertId();
}
// Transactions (begin, end, cancel)
public function beginTransaction(){
return $this->dbh->beginTransaction();
}
public function endTransaction(){
return $this->dbh->commit();
}
public function cancelTransaction(){
return $this->dbh->rollBack();
}
// Get debug dump
public function debugDumpParams(){
return $this->stmt->debugDumpParams();
}
}
＆GT;
这是config.php，我在其中定义了DB_HOST，DB_USER，DB_PASS和DB_NAME。
<?PHP
// Define configuration
define('DB_HOST', 'localhost');
define('DB_USER', 'someuser');
define('DB_PASS', 'someoassword');
define('DB_NAME', 'somedb');
// File includes
include('dbConnect.php');
＆GT;
这是查询，在register.php（抱歉，我之前忘了）
<?PHP
// Include files
include('core/config.php');
$database = new Database();
$database->query('INSERT INTO users (FName, LName, Age, Gender) VALUES (:fname, :lname, :age, :gender)');
$database->bind(':fname', 'Kane');
$database->bind(':lname', 'Steuer');
$database->bind(':age', '20');
$database->bind(':gender', 'male');
$database->execute();
echo $database->lastInsertId();
echo $database->debugDumpParams();
＆GT;