Re: SQL select via logicals

Walden

At 01:18 PM 11/25/97 -0500, you wrote:
>Am I losing my mind? (Don't answer that!) Anyway, if I am issuing a select
>over a logical and that logical has select/omit but I do NOT specify that
>select/omit in my where clause I thought that SQL would not use that select
>criteria. I just saw an example that led me to believe that this was not the
>case. That is to say, if I select * from lgl1 and lgl1 has select criteria
>then the select will only have the records in the result set that match the
>selection criteria. Am I nuts?

Without looking at manuals, I've always assumed that if you specify a
logical with select/omit criteria, that's all that'll come back. That's why
I always recommend naming the physical in the SQL statement and let the
system work out the details. Naming a logical seems to have no effect on
what access paths actually get used. I think (_from_ reading about the
optimizer), that the where and group by and order by stuff are used. Maybe
that's the basis of what you thought, that naming a logical has no
effect—on the optimizer.

But, maybe, especially in the case of S/O logicals, the result set returned
is a different animal than the action of the optimizer. Eh?

Cheers

Vernon Hamberg
Systems Software Programmer
Old Republic National Title Insurance Company
400 Second Avenue South
Minneapolis, MN 55401
(612) 371-1111 x480


+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to "MIDRANGE-L@midrange.com".
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---