<?php include "connect.php"; ?>
<?php
    $id = $_GET['edit'];
    $result = mysqli_query($mysqli,"SELECT * FROM inventory_table WHERE id=$id");
    $user_data = mysqli_fetch_object($result);
?>

<form action="" method="POST">
    ITEM NAME : <input type="text" name="item_name" value="<?php echo $user_data->item_name; ?>"><br>
    QUANTITY : <input type="number" name="quantity" value="<?php echo $user_data->quantity; ?>"><br>
    PRICE : <input type="text" name="price" value="<?php echo $user_data->price; ?>"><br>
    <input type="submit" name="submit" value="SUBMIT">
</form>

<?php
    if(isset($_POST['submit'])){
        $item_name = $_POST['item_name'];
        $quantity  = $_POST['quantity'];
        $price     = $_POST['price'];

        $query = "UPDATE inventory_table SET item_name = '$item_name',
                                        quantity  = '$quantity',
                                        price     = '$price'
                                  WHERE id        = '$id'";
       $update = mysqli_query($mysqli,$query);

       if($update){ ?>
            <script>window.location = 'index.php';</script>
        <?php
       }
    }
?>