Linking to a subfile (was Subphyla question)

[Robert J.M. Edis]

Sorry Richard

I originally wrote to Matt privately as I didn't think it was of general
interest, but it got interesting when Bob waded in.

Blue 

-----Original Message-----
From: Richard Witkopp
To: 'powerh-l@list.swau.edu'
Sent: 3/1/00 1:19 PM
Subject: RE: Linking to a subfile (was Subphyla question)

Wow, I never received any of this discourse except maybe the
first message. I wonder if the problem is with the listserver
or our mail system here.

> G'day Matt, Bob
> 
> Actually you may have hit the nail on the head Bob.  The 
> report I mentioned
> to Matt did have a more complex ACCESS than I intimated.  It 
> was more along
> the lines of 
> 
> ACCESS table1 &
>   LINK TO table2 OPTIONAL &
>   LINK TO RECORD 0 OF *subfile
> 
> SELECT IF ....
> 
> This took about 45 minutes to run even though only a few 
> thousand records
> were involved.
> 
> By changing it to
> 
> ACCESS table1 &
>   LINK TO table2 OPTIONAL
> CHOOSE SYSTEMVALUE ...
> SELECT IF ...
> 
> reduced the run time down to about 5 minutes even though the 
> same number of
> records were read from the primary file.
> 
> Blue
> 
> -----Original Message-----
> From: Deskin, Bob
> To: Ohmes, Matt; 'Robert J.M. Edis'
> Sent: 3/1/00 6:40 AM
> Subject: RE: Subphyla question
> 
> Theoretically (love that) a link to a specific record of a 
> subfile (via
> LINK
> TO RECORD) should be treated like a link to a unique index. As long as
> the
> index value doesn't change, QUIZ doesn't read the record over 
> because it
> "knows" that the record already in the buffer is the correct 
> one. That's
> the
> simple case. However, if you throw in SELECTs and SELECT file IFs and
> OPTIONALs, the situation gets more complicated. There are cases where
> the
> input buffers are cleared because otherwise a DEFINE could be 
> evaluated
> using data belonging to another complex.
> 
> The way to test this is something like
> 
> ACCESS A LINK TO B LINK TO RECORD 0/1 OF C
> GO
> 
> The 0 or 1 to get the first record depends on the platform. C can be a
> direct file or a subfile, in which case put an asterisk on the front.
> 
> There should be very little difference between using C or not using C
> (ACCESS A LINK TO B). But of course you have to run something 
> that takes
> a
> reasonable amount of time because there will be file open overhead.
> 
> As Matt suggested, this used to work but probably hasn't been 
> checked in
> a
> long time. In fact I think it's documented that way, at least 
> somewhere
> in
> all the PH manuals on my shelves :-)
> 
> Bob
> 
> -----Original Message-----
> From: Ohmes, Matt 
> Sent: February 29, 2000 10:12 PM
> To: 'Robert J.M. Edis'
> Cc: Deskin, Bob
> Subject: RE: Subphyla question
> 
> 
> Hmmm... Well, to tell you the truth, I've never specifically 
> tested it,
> but
> I'd heard this is the way it worked.  And I've never had the type of
> performance problem you describe. I've used this technique a lot over
> the
> years and never saw the type of performance you described, but I've
> never
> specifically tried to test it. 
> 
> Now I must admit, I rarely worked on a UNIX box. My HP 
> experience almost
> exclusively on HP3000, but I've also used the technique extensively on
> VAX.
> 
> Also, were you accessing a relational table then linking to 
> the subfile?
> If
> so, the performance enhancement is almost certainly 
> attributable to the
> CHOOSE vs. a SELECT and not the Variable per se.  
> 
> Do I understand correctly the way we read a single record subfile Bob?
> Matt
> 
> -----Original Message-----
> From: Robert J.M. Edis [mailto:robert.edis@creatcomp.com]
> Sent: Tuesday, February 29, 2000 5:29 PM
> To: 'Ohmes, Matt '
> Subject: RE: Subphyla question
> 
> 
> G'day Matt
> 
> I have to challenge you on what you said about "Quiz will read the
> subfile
> record once".  I 'fixed' a report for a client last year on a 
> HP/UX box
> where a report was taking 45 minutes to run.  This report was 
> reading a
> table and linking to record 1 of a subfile.  It read the subfile for
> each
> occrrence on the primary file.
> 
> I replaced the logic using an environment variable and a CHOOSE on the
> primary file instead.  This reduced the run time to only 5 minutes.
> 
> Blue 
> 
> -----Original Message-----
> From: Ohmes, Matt
> To: 'Scott, Valerie'; POWERH-L@lists.swau.edu
> Sent: 2/29/00 5:48 PM
> Subject: RE: Subphyla question
> 
> Actually you can link to the subfile from your data file. Try this:
> 
> ACCESS datafile LINK TO RECORD 1 OF *subfile
> 
> SELECT IF dateitem of subfile = dateitem of datafile
> 
> Quiz will read the subfile record once and keep it in memory 
> through the
> entire run, so it should be quite effecient.  
> 
> You didn't say what machine you are on, but the above works 
> for VAX and
> UNIX
> (I believe). If you are on an HP3000, substitute a zero for the "1" in
> the
> ACCESS statement.
> 
> Matt
> 
> Matt.Ohmes@Cognos.Com
> Cognos Corporation
> 909 E. Las Colinas Blvd.
> Suite 1900
> Irving, TX  75039
> 214-259-6200
> "Matt doesn't really know anything.  He just likes to 
> pontificate a lot.
> We refuse to acknowledge that he works for Cognos or that we have ever
> met him or anyone with whom he's ever been associated.  Don't lend him
> money and don't let him talk to your sister!" ;-)
> 
> -----Original Message-----
> From: Scott, Valerie [mailto:vscott@solanocounty.com]
> Sent: Tuesday, February 29, 2000 4:30 PM
> To: POWERH-L@lists.swau.edu
> Subject: Subphyla question
> 
> 
> How can I avoid needing a parm prompt entry in all 4 passes 
> of a report?
> I
> am unable to pass the user date range beyond the first report.
> 
> I am writing a Quiz program that runs 4 passes of data.
> Each pass for data require the same user entered Date range.
> I created a one record subfile(a) to accept the PARM PROMPTED date
> value.
> On the first report, I use a USE to run the subfile(a), prompting for
> the
> date.
> The remaining reports access other files and append to a separate
> subfile,
> which at the end is sorted and reported by type of record.
> I don't believe I can link to my 'date' subfile, because the data file
> is
> driving the reporting.
> Once the date range is captured, is there a way to hold the dates,
> throughout all four passes?
> 
> Thank You,
> Valerie
> Solano County
> 
> 
>  
> 
> Thank you,
> 
> Valerie Scott
> 
> 
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