In the expanded view of the schemas directory, the data source/primary key pairs are shown: ADDRESS.xsd and ADDRESS_KEY.xsd; CUSTOMER.xsd and CUSTOMER_KEY.xsd; CUSTOMER_ORDER.xsd and CUSTOMER_ORDER_KEY.xsd; CUSTOMER_ORDER_LINE_ITEM.xsd and CUSTOMER_ORDER_LINE_ITEM_KEY.xsd; and PRODUCT.xsd and PRODUCT_KEY.xsd.