Laravel Seeder-使用唯一ID(UUID)更新所有记录

public function run(){
        $users = \App\User::get();

        try{
            DB::beginTransaction();
            foreach($users as $user){
                $user->public_id = Uuid::generate(4)->string;
                $user->save();  
            }
            DB::commit();
       }
       catch(Exception $e){  
           DB::rollback();
    }
   //if incase you get exception during database seeding.
}