validation - Laravel unique field validate not working -

i have have field called mac store mac address need unique avoid duplicate mac address.

code:

return [             'user_id' => 'required|integer',             'mac' => array('required|unique:mac', 'regex:/^([0-9a-z]{2}[-]){5}([0-9a-z]{1,2})$/'),         ]; 

error: method [validaterequired|unique] not exist.

structure:

create table `devices` (   `id` int(10) unsigned not null auto_increment,   `user_id` int(10) unsigned not null,   `name` varchar(255) collate utf8_unicode_ci not null,   `mac` varchar(255) collate utf8_unicode_ci not null,   `content` varchar(255) collate utf8_unicode_ci not null,   `status` tinyint(1) not null default '0',   `created_at` timestamp null default null,   `updated_at` timestamp null default null,   `deleted_at` timestamp null default null,   primary key (`id`),   unique key `devices_mac_unique` (`mac`),   key `devices_user_id_foreign` (`user_id`),   constraint `devices_user_id_foreign` foreign key (`user_id`) references `users` (`id`) on delete cascade ) engine=innodb auto_increment=3 default charset=utf8 collate=utf8_unicode_ci; 

you need define table mac address need checked against

return [     'user_id' => 'required|integer',     'mac'     => 'required|unique:devices,mac|regex:/^([0-9a-z]{2}[-]){5}([0-9a-z]{1,2})$/', ]; 

update - when updating record, instead of create extend rule to.

return [     'user_id' => 'required|integer',     'mac'     => 'required|unique:devices,mac,' . $device->id . '|regex:/^([0-9a-z]{2}[-]){5}([0-9a-z]{1,2})$/', ];