Sorting and filtering subfiles -- RPG400-L

>...create an empty temp file in QTEMP

I have been doing this for a long time with the subfiles that I create.  I
like to let the user filter and sort the subfile to their liking after the
initial load.   They can double click the headers or place the cursor on the
header and press enter.  I write out the subfile to a work file in qtemp,
which has the same fields with one extra "KEY" field.  I load the sorted
columns data into both the matching field and the "KEY" field, then reload
the subfile from the indexed work file in QTEMP.    I am sure there are fast
and better ways, but this has worked for years and I already have a
template(I do not like creating new every time...  I like to keep a small
library of templates or samples).

One of my purposes for monitoring this list is to find faster and better
ways of doing things.   Not to offend anyone, nor am I pointing fingers, or
to slam this topic or others... But, it often seems as though many of the
questions are things that were (or should have been) covered in the RPG 101
classroom.

Now that makes a full circle back to the school topics of a few weeks ago.

I guess I ought to duck for cover, but will close by saying I do enjoy
learning some new ideas and techniques.

Eurrat Saylor, Jr.
9562 East 750 North
Walkerton, IN  46574

tel. (574) 586-7970
fax (574) 586-2677
cel (574) 532-2898 (Eurrat)   Nextel 2-way 111*42*729




----- Original Message -----
From: "Tony Carolla" <carolla@xxxxxxxxx>
To: "RPG programming on the AS400 / iSeries" <rpg400-l@xxxxxxxxxxxx>
Sent: Tuesday, March 29, 2005 3:51 PM
Subject: Re: Arrays


> Hmmm... Well, I because the number of columns is finite, I would
> probably create seven empty temp files in QTEMP, each one with all of
> the subfile columns, and keyed based on one of the seven columns.  The
> first time the screen was displayed, I would populate the default sort
> order temp file with the results, then populate the subfile from this
> temp file.  Then, when a new column was selected, I would simply copy
> from the original temp file to one of the other seven, and populate
> the subfile from the new temp file.
>
> The copy would always be done from the default sort order temp file,
> and it would be done using blocked reads and writes (you could even
> size the blocking based on the number of records in the temp file),
> and using DSs to read and write to.  This would prevent having to
> re-populate the subfile from the database files, and only focus on the
> result set.
>
>
> On Tue, 29 Mar 2005 15:41:00 -0500, rob@xxxxxxxxx <rob@xxxxxxxxx> wrote:
> > Ok, I understand what you say about performance tuning.  RPG has those
> > issues too, like figuring out record blocking, primary vs SETLL/READ,
etc.
> >
> > Some application questions though.
> > 1)  If a user said "On this inquiry screen I would like to position my
> > cursor on any column and sort by that column (and you have seven
columns)
> > would you:
> > a - Create 7 logicals and use RPG native I/O
> > b - Front end the code with OPNQRYF (but since I don't use that I forget
> > if you have to redefine the key on the f-spec to match the sort order)
> > c - Use SQL
> > d - Tell the user it can't be done.
> > e - Offload the data to another platform and have them manipulate it
> > there.
> > f - Put it on your to-do list, but always at the bottom priority to
never
> > get done.
> >
> > Rob Berendt
> > --
> > Group Dekko Services, LLC
> > Dept 01.073
> > PO Box 2000
> > Dock 108
> > 6928N 400E
> > Kendallville, IN 46755
> > http://www.dekko.com
> >
> > Tony Carolla <carolla@xxxxxxxxx>
> > Sent by: rpg400-l-bounces@xxxxxxxxxxxx
> > 03/29/2005 02:03 PM
> > Please respond to
> > RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx>
> >
> > To
> > RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx>
> > cc
> >
> > Subject
> > Re: Arrays
> >
> >
> > <snip>
> > > SQL is well worth the coin paid to obtain it.  Harness it's power &
> > you'll
> > > never want to type the command WRKQRY again....
> > < Thanks,
> > < Tommy Holden
> > </snip>
> >
> > Haven't typed in WRKQRY in years (~10).
> >
> > > I don't find it "that complex".
> > > Even Joe Pluta occasionally finds SQL useful.  I think that if you
never
> > > use it, then it is like the person who finds he can get everything
done
> > > with a hammer; when it is the only tool in their toolbox.
> > >
> > > Rob Berendt
> >
> > I don't find SQL too complex by any means.  I find it simple, and have
> > used it on many platforms.
> >
> > I guess I see it this way:  You can build your SQL statements, and
> > build your summaries "on the fly" with no extra code (SQL is code,
> > BTW), but when you run them, and they take long, what can you do?
> > Index.  Study the query optimizer -- what is it choosing?  Why won't
> > it use my index?  Which type of index?  EVI?  Can I bribe the crazy
> > thing?  Will it use the index when the user hits the view a little
> > differently?
> >
> > I have spent alot of time studying indexing, on DB2 and SQL server as
> > well.  It is fascinating, but I just find it easier to analyze the
> > data request I am building, and make my own 'access plan', write the
> > code to do it, and it's done.  I would bet that any quick-running SQL
> > statement can be made to run just as fast or even faster using RPG.
> >
> > --
> > "Enter any 11-digit prime number to continue..."
> > --
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>
>
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> "Enter any 11-digit prime number to continue..."
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