crud delete not working anymore - php

Question

i used the crud delete method and it works for me, but when i tried it with a different database and table it keeps saying "Invalid argument supplied for foreach()"
this is my "vacature-verwijderen.php" where you should be able to delete it
<div>
<table id="tabel">
<thead>
<tr>
<th>Functie</th>
<th>Omschrijving</th>
<th>Salaris</th>
</tr>
</thead>
<tbody>
<?php
include 'database.php';
$pdo = Database::connect();
$sql = 'SELECT * FROM vacature ORDER BY id DESC';
foreach ($pdo->query($sql) as $row) {
echo '<tr>';
echo '<td>'. $row['functie'] . '</td>';
echo '<td>'. $row['omschrijving'] . '</td>';
echo '<td>'. $row['salaris'] . '</td>';
echo '<td width=250>';
echo '<a class="button " href="update.php?id='.$row['id'].'">Update</a>';
echo ' ';
echo '<a class="button" href="delete.php?id='.$row['id'].'">Delete</a>';
echo '</td>';
echo '</tr>';
}
Database::disconnect();
?>
</tbody>
</table>
</div>
</div>
and then when you click delete you go to "delete.php" which looks like this
<?php
require 'database.php';
$id = 0;
if ( !empty($_GET['id'])) {
$id = $_REQUEST['id'];
}
if ( !empty($_POST)) {
$id = $_POST['id'];
$pdo = Database::connect();
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "DELETE FROM vacature WHERE id = ?";
$q = $pdo->prepare($sql);
$q->execute(array($id));
Database::disconnect();
header("Location: vacature-verwijderen.php");
}
?>
i don't know what is wrong since it used to work, also my database table looks like this

Answer 1

foreach ($pdo->query($sql) as $row) {
That's what is wrong. $pdo->query($sql) already returns your $row.
Use a while instead so that it do the query and returns you the new row as long as there is data to fetch :
while ($row = $pdo->query($sql)) {
Also :
$sql = "DELETE FROM vacature WHERE id = ?";
The table you provided doesn't contain any field named id, although there is one named vacature_id. You might want to change that too :
$sql = "DELETE FROM vacature WHERE vacature_id = ?";
Don't hesitate to come back if it doesn't solve your issue.