sales_order => [ "SL::DB::Order", [ sales => 1, quotation => 0 ] ],
sales_quotation => [ "SL::DB::Order", [ sales => 1, quotation => 1 ] ],
purchase_order => [ "SL::DB::Order", [ sales => 0, quotation => 1 ] ],
- sales_delivery_order => [ "SL::DB::DeliveryOrder", [ is_sales => 1 ] ],
+ sales_delivery_order => [ "SL::DB::DeliveryOrder", [ order_type => 'sales_delivery_order' ] ],
);