2 parents node per 1 child node in xml?

when i create a xml file from this relationship tabes, i get a problem. I cannot create Orderdetails table because it is a child from 2 parent. example, original Oderdetails table:

OrderID  ProductID  UnitPrice  Quantity  Discount

1               2               14$          20          0.3

Orderdetails table when i create by xml file

OrderID  ProductID  UnitPrice  Quantity  Discount

                2               14$          20          0.3

1                               14$          20          0.3