Charles Hooper wrote:
> klabu wrote:
>> Assuming you don't know anything about these 3 tables beyond FK & PK
>>
>> select *
>> from A, B, C
>> where A.fk = C.pk
>> and B.fk = C.pk
>>
>> Is this JOIN "complete" ?
>> or an additional predicate is needed between A and B ?
>>
>>
>> thanks
>
> Transitive closure:
> A = C
> B = C
> Logic states that this implies that:
> A = B
>
> Perform a 10053 trace, you may see the Cost Based optimizer adding a
> constraint like this:
> A.FK = B.FK
>
> Charles Hooper
> PC Support Specialist
> K&M Machine-Fabricating, Inc.
Which, if it were true, would indicate a bad design.
--
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 - 15:11:50 CDT
