Is it ok to have transaction at Presentation level?

Question

Let's assume that I have an Order object that has a List<OrderItem> , the user goes to page and creates his order, now I should save his selection to the database, I have two data service classes one for each entity, OrderDataService and OrderItemDataService, which is more correct?

1- At presentation level in the Add button I write a code that calls OrderDataService.Add(Order order) method then loop through List<OrderItem> and call OrderItemDataService.Add(OrderItem item) for each OrderItem making the transaction happen at the level of presentation behind the Add button.

OR

2- Create a method in the OrderService.AddWithItems(Order order, List<OrderItem> items) that takes Order and OrderItem as parameter and make this method handle the looping and transaction?

Note: This is a very simple example, in practice things are more complicated and creating an OrderService.AddWithItems() method could end up taking too many paramters.

Answer 1

If you have an order object that has a list of items in it I would expect a service with an add method taking an order to save all of the order which includes the items. There shouldn't need to be additional parameters to add an order, the order object should know everything about orders, there shouldn't be a need to pass items, customers, or anything else outside of the order object, at least when adding an order.