Re: check constraint

Well, I don't think so: the problem concerns one record of A and one
record of C. This means that they would be 2 different records of the
table which both A and C inherit. The problem stays.

Le dim 08/06/2003 à 21:02, Patrick Welche a écrit :
> > >>On Mon, Jun 02, 2003 at 10:52:00 +0200,
> > >>  erwan ancel <erwan.ancel@free.fr> wrote:
> > >>> Hi,
> > >>> I would like to know if it is possible to set "complex" constraints on
> > >>> databases such as:
> > >>>
> > >>> A->B means that in table A, each record references a record of table B
> > >>> (or NULL)
> > >>>
> > >>> so we have:
> > >>>
> > >>> A->B
> > >>> C->B
> > >>> D->C
> > >>> D->A
> > >>> constraint: for one record of D, D->A->B = D->C->B
>
> Could inheritance be used?
>
>    D -> A -> B
>    D -> C -> B
>
> suggests that A and C are similar. I have never tried using inheritance -
> could you put the constraints on a table which both A and C inherit?
>
> Cheers,
>
> Patrick
>