Re: create assertion?

It's essentially a fancy check constraint. See http://remote.science.uva.nl/~mdr/Teaching/RDB/0102/Silberschatz/3rdEdition/ chapter6.pdf

I don't think Oracle 9.2 supports the Create Assertion command, so you'll have to use a trigger.

--
Terry Dykstra
Canadian Forest Oil Ltd.
"Daniel Morgan" <dmorgan_at_exesolutions.com> wrote in message
news:3D7CCECD.53500D62_at_exesolutions.com...


> eugene kim wrote:

>

> > is there an equivalent of 'create assertion' in oracle?

> > or do i have to get around with triggers?

> >

> > desired assertion is like this

> > ------------

> > no team may play two games in two different places on the same day..

> > ------------

> > this is how i'm trying..

> >

> > create or replace trigger assertion_on_game

> >         before insert or update on games

> > for each row

> > begin

> >         if exists ( select home_team_id

> >                 from teams t

> >                 where t.home_team_id = :new.visitor_team_id or --

 inserted


> >  visitor team has game in home city

> >                 t.visitor_team_id = :new.home_team_id and -- inserted

 home


> > team has game in visitor city

> >                 game_date = :new.game_date) then

> >         <don't update or insert>

> >         end if;

> > end;

> > /

> >

> > thank you

>

> Any chance you could translate the word ASSERTION into Oracle. I haven't a

> clue what you are talking about and I would expect most people are

 thinking


> the same thing.

>

> Daniel Morgan

>