Re: SQL select via logicals

[John Carr <74711.77@xxxxxxxxxxxxxx>]

RE:     Re: SQL select via logicals

Chris said;
> Okay, look, here's my question. If I issue and SQL request against a logical
> and the logical is built with select/omit criteria, will the records
> returned be filtered by the s/o criteria? 
> I have always counted on this for query, but I don't know if SQL behaves the
> same way. I would expect it to, since I might give access to a logical for
> purposes of security.


As I said a few posts ago,  You will only see the information the logical
or view is able to present.  This includes both Selection & Projection.

If you have a logical or view with a subset of the fields in the physical,
you will only see that subset(Projection).

If you have a logical that has some Select/Omit(Selection) you will only
see that subset.  

Both in a HLL and using SQL.

P.S.
     Paul, I am trying to get an answer of how fast the optimizer stops 
look for candidate indexes before giving up.  I really believe it is still
based on the chronilogical creation date.  So most importantly PLAN your
data base.  Create your logicals in the order of the highest frequency of
use.  Don't create the logical that will most often used by Query/400 or
SQL last (like number 15 or 25 or even 50th in your case Paul).

I also think it would be good to have a mechanism to force the inspection
of all indexes before deciding to Sort, or Copy the data or Build an Index
on the fly. 

But I can't imagine how they would implement it.  I can see a new parameter
on OPNQRYF but can't see how they would implement it in SQL. Unless it was
a system wide System Value.

John Carr
EdgeTech
Consulting / Software / Classroom Education
804-739-7689 Phone
804-739-7950 Fax

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