CREATE OR REPLACE VIEW V_PARTY_RELATIONSHIPS AS
SELECT from_parl.prty_id AS from_parl_prty_id
      ,prtp.from_rt_code
      ,to_parl.prty_id AS to_parl_prty_id
      ,prtp.to_rt_code
      ,prtp.description
      ,greatest(from_parl.start_date
               ,prel.start_date
               ,to_parl.start_date) AS effective_start
      ,least(nvl(from_parl.end_date
                ,to_date('31-dec-2099'
                        ,'dd-mon-yyyy'))
            ,nvl(to_parl.end_date
                ,to_date('31-dec-2099'
                        ,'dd-mon-yyyy'))
            ,nvl(prel.end_date
                ,to_date('31-dec-2099'
                        ,'dd-mon-yyyy'))) AS effective_end
  FROM (SELECT prty.first_name
              ,prty.last_name
              ,prty.username
              ,parl.prty_id
              ,parl.rt_code
              ,parl.id
              ,parl.start_date
              ,parl.end_date
          FROM parties     prty
              ,party_roles parl
         WHERE parl.prty_id = prty.id) from_parl
      ,(SELECT prty.first_name
              ,prty.last_name
              ,prty.username
              ,parl.prty_id
              ,parl.rt_code
              ,parl.id
              ,parl.start_date
              ,parl.end_date
          FROM parties     prty
              ,party_roles parl
         WHERE parl.prty_id = prty.id) to_parl
      ,party_relationship_types prtp
      ,party_relationships prel
 WHERE prel.from_parl_id = from_parl.id
   AND prel.from_parl_prty_id = from_parl.prty_id
   AND prel.from_parl_rt_code = from_parl.rt_code
   AND prel.to_parl_id = to_parl.id
   AND prel.to_parl_prty_id = to_parl.prty_id
   AND prel.to_parl_rt_code = to_parl.rt_code
   AND prtp.from_rt_code = prel.from_parl_rt_code
   AND prtp.to_rt_code = prel.to_parl_rt_code;