I have this schema:

I want to insert an Order with OrderItems into database, so I wrote this method:

    public void SaveOrder(Order order)
    {
        using (var repository = new StoreEntities())
        {
            // Add order.
            repository.Orders.AddObject(order);

            // Add order items.
            foreach (OrderItem orderItem in order.OrderItems)
            {
                repository.OrderItems.AddObject(orderItem);
            }

            repository.SaveChanges();
        }
    }

Everything is inserted just fine, except that new Product records are inserted too, which is not what I want.

What I want is to insert Order and its OrderItems, without going any further down the object graph. How can that be achieved?

Any help is really appreciated, thank you.