Datenbanksysteme I, SS 2005

create view seetiefe(g_id, tiefe) as
select g_id, tiefe
from   see;

create view seetiefe(tiefe) as
select tiefe
from   see;

create view einwproland(l_id, anzahl) as
select l_id, sum(einwohner)
from   landesteil
group by l_id;

create view konsistenteinwohner(l_id, name, hstadt) as
select l.l_id, l.name, l.hauptstadt
from   land l
where  einwohner = (select sum(einwohner)
                    from   landesteil lt
                    where  lt.l_id = l.l_id);

create view tiefeseen(g_id, name) as
select g.g_id, g.name
from   gewaesser g, see s
where  g.g_id = s.g_id
and    s.tiefe > 500;

create view tiefeseen(g_id, name) as
select g_id, name
from   gewaesser
where  g_id in (select g_id
                from   see
                where  tiefe > 500);