Is it possible to define primaryKey on runtime for Laravel / Eloquent? -

in eloquent, know it's possible define table on runtime $model->settable().

i tried adding new item in constructor like:

$mymodel = new \mymodel(array(), 'my_primary_key'); $mymodel->settable('mytable'); 

with constructor being:

class mymodel extends eloquent {      public function __construct($attributes = array(), $primarykey = 'id') {         parent::__construct($attributes); // eloquent         $this->primarykey = $primarykey;     } } 

that makes $primarykey = 'id' default. - 1 doesn't work cause doesn't change primarykey whatever define in call constructor, gets default ('id'). if don't set default following error:

 missing argument 3 mymodel::__construct(), called in  /vendor/laravel/framework/src/illuminate/database/eloquent/model.php on line 517 , defined 

i tried:

 $mymodel->setattribute('primarykey', 'my_primary_key'); 

but 1 doesn't set attribute

but nothing works. default laravel having 'id' primarykey, in tables have things 'car_id' table cars, , on, errors like:

 column not found: 1054 unknown column 'id' in 'where clause'   (sql: select * `cars`      `id` = 1 limit 1) 

i tried code: https://github.com/laravel/framework/blob/master/src/illuminate/database/eloquent/model.php#l1415, doesn't have method set on runtime.