如何创建安全高效的 PDO 插入/更新帮助函数？

function dbSet($fields, &$values) {
    $set = '';
    $values = array();

    foreach ($fields as $field) {
        if (isset($_POST[$field])) {
            $set .= "`$field` = ?,";
            $values[] = $_POST[$field];
        }
    }

    return rtrim($set, ',');
}

$fields = explode(" ","name surname lastname address zip fax phone date");
$_POST['date'] = $_POST['y']."-".$_POST['m']."-"$_POST['d'];

$query  = "UPDATE $table SET ".dbSet($fields, $values).", stamp=NOW() WHERE>

$table = new Table();
$table->fromArray($_POST);
$table->save();