致命错误：在非对象

Question

我知道这是一个重复的问题，但我无法找到答案，而且我是php＆amp; MySQL的！

这是用于更新我的数据库名为＆＃34; Assignmentdb＆＃34;

我想更新商品名称，价格，说明和尺寸。

我收到此错误：

  

    

致命错误：在第89行的/Applications/XAMPP/xamppfiles/htdocs/Assignment/itemupdate.php中调用非对象的成员函数bind_param（）

  

这是我的代码：

<?
session_start();
ob_start();
If (!isset($_SESSION["userid"])){
        $_SESSION['userid'] = $userid;
            header("Location:login.html");
        }
else {
$userid = $_SESSION['userid'];
}
$prd_id = $_GET['prd_id'];
    echo "<b>Item ID:</b> $prd_id <br>";

        if(!empty($_POST['itemname'])) {
            $itemname = $_POST['itemname'];
            $price = $_POST['price'];
            $description = $_POST['description'];
            $measurements = $_POST['measurements'];
            echo "Item Name: $itemname <br>";
            echo "Price: $price <br><br>";
            echo "Item measurement: $measurements <br>";
            echo "Item description: $description <br><br>";
        }
        else {
            $itemname = null;
            echo "Please Try Again!";
        }



        if ($prd_id && $itemname && $price && $description && $measurements) {
            $mysqli = new mysqli("localhost", "root", null, "Assignmentdb") ;
            $stmt = $mysqli->prepare("UPDATE Item SET itemname=?, price=? description=? measurements=? WHERE prd_id=?"); 
            $stmt->bind_param("ssssi", $itemname, $price, $description, $measurements, $prd_id); 
            $stmt->execute();
            $stmt->close();
            $mysqli->close();
        }
        else {
            echo 'Please <A HREF="javascript:javascript:history.go(-3)"> Click Here</a> to go back.<br>';
        }

ob_end_flush()  
?>