Re: Is this JOIN good ?

From: DA Morgan <damorgan_at_psoug.org>
Date: Mon, 16 Oct 2006 13:11:11 -0700
Message-ID: <1161029466.585230@bubbleator.drizzle.com>

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

The business rules.

Constraints are intended to enforce business rules. The business rules are the only thing that matters.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org

Received on Mon Oct 16 2006 - 15:11:11 CDT