Scrolling Cache

[Deskin, Bob]

I too would be interested in hearing specific ideas on the caching
"problem". Has anyone used caching with users that are not already
PowerHouse users? I suspect much of the confusion is based on the
expectation that caching should work the same way as PowerHouse used to
work. Keep in mind that before caching, the records that you saw were the
records in the buffer, no more, no less. With caching, the display is a
window into the buffers and you can move the window back and forth, possibly
seeing the same record more than once.

Here's a test. Set up a simple cache screen such that you have more records
in the cache than are displayed. Retrieve records before you bring in the
user. Now tell the user to scroll back and forth and change selected
records. Make sure that the change list forces the user to go to the end of
the cache and then backwards. I'll be the user sees the same record more
than once and thinks nothing of it. Now do the same test, but have the user
change records in order. Now when the user sees the same record, he/she may
be confused as to whether it's a duplicate.

As for specific enhancements and messages, please let me know. No promises
but you never know :-)

Bob Deskin              
Senior Product Advisor, Application Development Tools, Cognos Inc.
bob.deskin@cognos.com (613) 738-1338 ext 4205 FAX: (613) 228-3149
3755 Riverside Drive P.O. Box 9707 Stn. T, Ottawa ON K1G 4K9 CANADA


-----Original Message-----
From: Terry Pickering [mailto:pickering@myself.com]
Sent: Wednesday, May 12, 1999 8:49 PM
To: powerh-l@lists.swau.edu
Subject: Scrolling Cache


Greetings All -

I'm in the last stages of putting a new system up using Powerhouse 7.10F4
on the Alpha. I'm taking advantage of some of the newer features such as
using a cache to scroll forwards and backwards through detail records.
Typically I use it when I have a screen using the OCCURS to display 10
lines of detail records. It's easy to use and works just fine. On some of
the screens, I've added some temp fields to display which records in the
cache are being displayed. 

For example if my "window" is 8 records, and I have 11 records in the
cache, it will display RECORDS 1-8 OF 11.

When you display the next screen of data (by pressing the Next Screen key
on the keyboard - same as NEXT DATA), it then displays RECORDS 5-11 OF 11.

Here is the problem - When I showed this to some of the users they were
confused (and I have to agree it is confusing at first) because it
"appeared" to display some of the records twice. Because of the way the
scrolling works, when you get to the end of the cache, it displays a "blank
record" on the last line of the cluster with the previous 9 records. What
is even more confusing is that if they don't notice it's the end, they
press the Next Screen again. This then starts displaying the cache again
starting at record 1.

I understand how this works and the concept/theory behind occurrence
window. I really like the functionality this offers to do this, but I also
think the following would make this a little more "user friendly". What are
others that are using CACHE and detail records think? Would it make sense
to ask for this as an enhancement, or have you come up with a work-around
for it.


1) When you scroll forward to the END of the cache or the last record - it
should display a message similar to if you try to scroll backwards to the
beginning of the cache ("Limit for backwards scrolling reached"). Not sure
why Cognos doesn't do this.

2) When displaying the last "n" records, don't fill the page (thereby re
displaying previously displayed records). Instead display it the same as if
you did not have cache turned out. Since you can scroll backwards, you can
always do that if you want. But the way it is now, the users think they
have transactions "duplicated".


Terry Pickering                         CompuGroup, Inc.
pickering@myself.com                    Portland, Oregon USA
www.teleport.com/~compugrp              Cessna 172 & Lancair ES

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