Question about Scrolling Cache

[Deskin, Bob]

7.29 was the first version on MPE/iX to allow cached files and scrolling
records. For details, see the manual. The warning referes to the way FOR
loops are now generated, with a MISSING option. It basically means that the
FOR loop should be executed for each occurrence that does not have an
associated record. This is based on the internal counters QUICK keeps.
Without the CACHE option on the FILE statement, there shouldn't be any
functional difference. However, there are some new commands like First
Record, Last Record, Next Record, and Previous Record that are used with
scrolling records. These will not work as expected with the MISSING option.
So the warning message says exactly what it means if you know about
scrolling records.

As for what you can store in the cache, you can have a maximum of 255
records in the cache, but there are some limitations as to the combinations.
A repeating PRIMARY or a repeating DETAIL can be cached. Everything else
relates to one or the other of those. Please refer to the manual.

By the way, if you do use caching, you will notice some differences in the
way QUICK displays the end of records retrieved. You also may see the same
record more than once as you scroll through the cache. Keep in mind that you
are moving back and forth in a group of records. It's like a window into a
list. In QUICK, we're used to moving forward through the file and only
seeing each record once.

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


> ----------
> From: 	COLIN GLASS[SMTP:cglass@mlcc.mb.ca]
> Sent: 	Monday, September 14, 1998 11:38 AM
> To: 	powerh-l@lists.swau.edu
> Subject: 	Question about Scrolling Cache
> 
> We have just upgraded to 7.29 on the HP3000.  In our Qdesign program, we
> have the Procedure Find written (I know this is a no-no, but the person
> who
> wrote it probably didn't).  Anyways, when the program is compiled, we
> receive the following warning:
> *W* FOR loop without missing option in FIND procedure.  Scrolling cache
> commands should be avoided.
> 
> 1.  What does this message mean in English?
> 
> 2.  How much information can be stored in scrolling cache?
> 
> Colin Glass
> Manitoba Liquor Control Commission
> Winnipeg, MB, Canada
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