Re: Is this JOIN good ?

Aleks wrote:
> klabu wrote:
> > "DA Morgan"
> > > Based upon what you posted I would say that it is impossible to tell.
> > > Is a.fk the child of c.pk? I don't know.
> > > Is b.fk the child of c.pk? I don't know.
> > > And even if they are ... it is impossible to know if these single
> > > relationships are sufficient to avoid a Cartesian product.
> > > --
> >
> > thanks
> > Yes, assuming they are of 100% referential integrity there, 100% "Children
> > <==> Parent" relationship
> > So given this it is still
> > "impossible to know if these single relationships are sufficient to avoid a
> > Cartesian product." ?
> >
> > What additional info do you need to know to say "JOIN is complete" ?
> >
> > thanks
> > 10gR2
>
> YES, It is complete. It is not Cartesian. You will get rows that exists
> in A, B, and C.
> Oracle will join A and C and then selected rows with B or
> will join B and C and then result with A.
>
> Thanks,
> Aleks

My ERROR! It is Cartesian for A and B. In this case to elimiante duplicate rows better to use Inline Select. (not Join)

Thanks,
Aleks. Received on Tue Oct 17 2006 - 12:52:25 CDT