PHP - Come verificare il record cancellato correttamente

Puoi utilizzare mysqli.affected-rows .

Considera quanto segue:

$query="delete from exam where eid='$eid'";
if ($con->query($query)==TRUE && $con->affected_rows > 0) {
    echo " record deleted";
} else {
    echo "Error: " . $query . "<br>" . $con->error;
}