-- Create a view glueing PO_History and PO_Archive together as the
-- full bitemporal table
CREATE VIEW Prop_Owner
 ( customer_number, property_number, VT_Begin, VT_End, TT_Start, TT_Stop )
 AS
 ( SELECT customer_number, property_number, VT_Begin, 
          VT_End, TT_Start, SYSDATE
   FROM PO_History
 UNION
   SELECT * FROM PO_Archive
 );
