cannot edit column in supplier_shop

[MrGumby]

Using PrestaShop 1.6.0.5

 

I want store information per supplier, per shop, so I decide create new column for it in `supplier_shop` table. Namely it is column `margin`.

 

To  be able to edit it from BO, I created override of AdminSupplierController and Supplier class. I can see values from DB when click edit, but when I click save, it throws error:

Unknown column 'margin' in 'field list'

UPDATE `ps_supplier` SET `id_supplier` = '2',`name` = 'name',`active` = '1',`date_add` = '2014-02-19 22:26:10',`date_upd` = '2014-04-01 22:00:18',`margin` = '50' WHERE `id_supplier` = 2

That is because it tries insert all data into `supplier` table, it did not create join with shop table counterpart, but it fetches data properly, so problem is only with insert statement.

 

My overrides are like this:

 

AdminSuppliersController.php

class AdminSuppliersController extends AdminSuppliersControllerCore
{
// modify only this method 
	public function renderForm()
	{
		...                
// modify fields_form array
		$this->fields_form = array(
		    'legend' => array(
			'title' => $this->l('Suppliers'),
			'icon' => 'icon-truck'
		    ),
		    'input' => array(
			array(
			    'type' => 'hidden',
			    'name' => 'id_address',
			),
                        ...


// add this element to fields_form
			array(
			    'type' => 'text',
			    'label' => $this->l('Margin rate'),
			    'name' => 'margin',
// experiment with add 'shop' => true did not help, but neither breaks anything
			    'shop' => true,
			    'col' => 2,
			    'hint' => $this->l('Basic margin for supplier, used to compute minimal price of items '),
                        ...

			
			)
		    ),
		    'submit' => array(
			'title' => $this->l('Save'),
		    )
		);

// call AdminController:: instead parent::
		return AdminController::renderForm();
	}

}

Supplier.php

class Supplier extends SupplierCore
{
	/** @var float supplier margin */
	public $margin;

	public function __construct($id = null, $id_lang = null)
	{
		self::$definition['fields']['margin'] = array('type' => self::TYPE_FLOAT, 'shop' => true, 'validate' => 'isFloat');
		parent::__construct($id, $id_lang);
	}

}

I searched for method that handles inserting in Supplier class, but I cannot get my head around it. If could someone lend helpful hand, It will be much appreciated.