Delete li entry in database with PHP - php

Question

I am working on a website where the user can enter the money he owes a friend. On one page the user can see all the entrys he made so far and should be able to delete them aswell. All entrys are inserted in a DB. For this overview page I use following structure:
<ul class="list-group">
<?php
$isEmpty = true;
while ($data = mysql_fetch_array($res)) {
if ($data['isDebt'] == 0) {
$isEmpty = false; ?>
<form method="post" action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']); ?>" autocomplete="off">
<li class="list-group-item" name="Debt_ID" value="<?php echo $data['Debt_ID'] ?>"><span class="badge"><?php echo $data['value']; ?></span><?php echo $data['name']; ?>
<button name="delete" type="submit" id="delete" class="btn btn-xs btn-danger pull-right">
<span class="glyphicon glyphicon-trash" aria-hidden="true"></span>
</button>
</li>
</form>
<?php }
}
if ($isEmpty) { ?>
<li class="list-group-item">No debt!</li>
<?php
} ?>
</ul>
One debt entry has the following values:
Debt_ID (numeric)
Name (like "pizza from jack")
Value (the price. for example "10")
The button for each li element should delete the entry in the DB via Debt_ID. I've used the following SQL statement so far:
DELETE FROM Debt WHERE Debt_ID='$debt_ID';
In PHP it looked like this:
if (isset($_GET['delete'])) {
$debt_ID = trim($_POST['Debt_ID']);
$res = mysql_query("DELETE FROM Debt WHERE Debt_ID='$debt_ID';");
if ($res) {
$errTyp = "success";
$errMSG = "Successfully deleted";
} else {
$errTyp = "danger";
$errMSG = "Error occured";
}
}
My problem right now is that I am not able to get the Debt_ID which I've entered with PHP in the li element. Does anyone know a better approach or what I am doing wrong?
I am developping with Cloud9 so I could invite someone if interested.

Answer 1

When you load all the debts, you can do that with a select statement and loop through the result set. In the loop you can put the id in hidden inputs in each li element:
$sql = "SELECT debt_id, name, value FROM debts WHERE user_id = " . $user_id;
$result = $conn -> query($sql);
if ($result -> num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
echo '<li>
<span>' . $row["name"] . '</span>
<span>' . $row["value"] . '</span>
<input type="hidden" value="' . $row['debt_id'] . ' name="id-to-delete">
</li>';
}
} else {
echo "no results";
}
The delete.php file should contain:
<?php
if (isset($_POST['id-to-delete'])) {
$idToDelete = $_POST['id-to-delete'];
// sql to delete a record
$sql = 'DELETE FROM debts WHERE debt_id=' . $idToDelete;
if ($conn->query($sql)) {
echo "Record deleted successfully";
} else {
echo "Error deleting record: " . $conn->error;
}
}
?>

Answer 2

After the form element simply add
<input type="hidden" name="Debt_ID" value="<?php echo $data['Debt_ID'] ?>">
Then remove the same information from the li element.
When submitting a form, input elements with a name attribute are what gets passed along to the next page.