foreach 中的表单操作仅适用于 php 的第一个值

Question

I have created a form where every time, it would store a different id during foreach loop

 <?php foreach ($res as $r) { ?> <form id="clearitem" action="clearitem.php" method="POST" enctype="multipart/form-data"> <input type="text" name="clearitem" value="<?php echo $r['cart_id'];?>"> <button type="Submit">&times;</button> </form> <?php } ?>

and the retrieval of the data works perfectly, it shows me each and every id one after another, but when I click the button (in this case to clear the item) it only works for the first value ie if I click the button for the second or the third value, it deletes the first one only, not the one corresponding to the button.

please do help, why this is happening and the appropriate solution, if anyone can provide!

the clearitem.php

 if(isset($_POST['clearitem'])){ $clear=$_POST['clearitem']; $sql = "DELETE FROM cart WHERE id=".$clear; if ($conn->query($sql) === TRUE) { echo "Record deleted successfully of id".$clear; } else { echo "Error deleting record: " . $conn->error; } }

Answer 1

So, I was able to solve this issue, and the solution is the "id" so when you are using foreach, for every iteration, it is re-creating the form with the different value of the input, of course!

But the problem is the id-field, even if the input value is different, but the id is same for every iteration and therefore, even if you click a different button ie the 2nd or 3rd, the POST request will consider the initial value as the actual value, ie the first iteration, just because the id was same!

It's similar to the concept of first-come-first-serve. Since the POST request getting the value of the first element correspondent to the id, therefore that will the final value of that specific id and no amount how many times you iterate, the value will not be updated if you use the same id.

The possible fix is to have a different id, with each different iteration and that was made possible with putting the foreach value in the id.

 <?php foreach ($res as $r) { ?> <form id="clearitem<?php echo $r['cart_id'];?>" action="clearitem.php" method="POST" enctype="multipart/form-data"> <input type="text" name="clearitem" value="<?php echo $r['cart_id'];?>"> <button type="Submit">&times;</button> </form> <?php } ?>

by this for every iteration, the value of the id will be different, like if cart_id are as:1, 2, 3 then the ids would be clearitem1, clearitem2, clearitem3. By this the POST request will be retrieving different values since the ids are different!

Answer 2

The system should be able to correctly process the submitted data according to the data value in each form in such a "multi-form" environment.

Hence the code below should work (tested):

<?php

$conn = new mysqli("localhost","dbuser","dbpassword","dbname");

$sql = "SELECT * FROM cart";
$stmt = $conn->prepare($sql); 
$stmt->execute();
$res = $stmt->get_result();

foreach ($res as $r) {
?>

<form id="clearitem" action="clearitem.php" method="POST" enctype="multipart/form-data">
<input type="text" name="clearitem" value="<?php echo $r['cart_id'];?>">
<button type="Submit">&times;</button>
</form>
<?php } ?>

The following is the clearitem.php code

<?php

if (isset($_POST["clearitem"])) {

$conn = new mysqli("localhost","dbuser","dbpassword","dbname");
$sql = "delete FROM cart where cart_id=?" ;
$stmt = $conn->prepare($sql); 

$id=$_POST["clearitem"]; 
$stmt->bind_param("i", $id);
$stmt->execute();
}
?>

<script>
    alert("Done !");
    if ('referrer' in document) {
        window.location = document.referrer;
        /* OR */
        //location.replace(document.referrer);
    } else {
        window.history.back();
    }
</script>