无法将数据插入数据库

Question

我正在尝试创建一个 crud 应用程序，但我无法在我的数据库中插入任何内容

请帮助我，因为我无法弄清楚

我的代码：https://pastebin.com/Ef8FdQ4G

<?php
include 'dbcon.php';
if(isset($_POST['add_data'])) {
    
    $name = $_POST['name'];
    $description = $_POST['description'];
    $duration = $_POST['duration'];
    $price = $_POST['price'];

    if($name == "" || empty($name)) {
        header('location:index.php?message= you need to fill in your name');
    
    }
    else {

        $query = "insert into `courses` (`name,` `description`, `duration`, `price`) values ('$name', '$description', '$duration', '$price')";

        $result = mysqli_query($connection,$query);

        if(!$result) {
            die("query Failed".mysqli_error());
        }

        else {
            header('location:index.php?insert_msg= your data has been added');
        }
    
    }
    
}


?>