cakephp - updating data without model with classRegistry -

i have table called user_tasks. not have model table , in totally unrelated controller have need update single field in user_tasks table.

this have tried far

 $user = classregistry::init('user_tasks');          $conditions = "user_id = ". $user_id;          $userrows = $user->find('first', array('conditions'=>$conditions));            $user->set(array(             'task' => $level         ));          $user->save(); 

however not $user->save(); , table never gets updated. can make work.

thanks

update:

in try / catch block, this

{"errorinfo":["hy000",1364,"field 'user_id' doesn't have default value"],"querystring":"insert `mytable`.`user_tasks` (`subscription`, `modified`, `created`) values ('latest', '2015-04-09 15:08:51', '2015-04-09 15:08:51')"} 

ok figured out. have send user id

so

$user = classregistry::init('user_tasks');

    $conditions = "user_id = ". $user_id;      $userrows = $user->find('first', array('conditions'=>$conditions));        $user->set(array(         'task' => $level,        'user_id' => $user_id     ));      $user->save(); 

the above create new record. if updating record pass primary key. , if passing primary key, not need user_id etc. need fields in set need updated.