You can create an XML definition by selecting multiple relational definitions and creating relationships between them. The Designer creates an XML view for each relational definition you import. The Designer converts every column in the relational definition and generates primary key-foreign key relationships. You can choose to create a root view.
The following figure shows a sample XML target definition from the relational definitions, Orders and Order_Items:
The root is XRoot. XRoot encloses Orders and Order Items. Order_Items has a foreign key that points to Orders.