我怎样才能在laravel 4中使用lockforupdate

Welcome all , I have problem in laravel 4 , when using lock for update statement
i want to prevent two users from updating the same record using RESTful Resource Controllers and Pessimistic Locking. Here is my view of edit

DB::table('users')->where('id', '=', $_get['id'])->lockForUpdate()->first();

and i want to check if row is locked before open edit page Regards