Re: OPNQRYF select process

[email@xxxxxxxxxxxxxxxxxxx (James W Kilgore)]

AFAIK, both the key fields and selections are searched, in order,
against existing logicals.

So to answer your question, yes.  It -may- make a difference.  I've also
been told that QRY will only search so many indexes (in order of
creation) before it gives up and builds it's own.

So I guess, the best you could do is to build individual logicals,
indexed by EMPNO and selected by YEAR and hope that the query optimizer
gets it.

Maybe create logicals like EMPL1999, EMPL1998, EMPL1997, etc. each
indexed by EMPNO, and within your process, pick the appropriate file
(instead of using a select clause) and the "EMPNO=1000" may trigger
OPNQRYF to use a "position cursor" kind of acceleration. (like you would
with a SETLL/READ loop)

HTH


 Loyd Goodbar wrote:
> 
> Does the order of selection criteria in OPNQRYF's QRYSLT parameter make a
> difference in which access path is chosen? If I have QRYSLT('EMPNO=1000 *AND
> YEAR=1999'), is it treated differently from QRYSLT('YEAR=1999 *AND
> EMPNO=1000')?
>
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