Re: simple questions-cannot find answers in common books

In <199812200656.WAA22274@law-f113.hotmail.com>, on 12/19/98 
   at 10:56 PM, "christopher sagayam" <christopher_70@hotmail.com> said:


>in rpg programming

>1.in form type I what is the use of SEQUENCE  eg.AA etc
   This is from the days of 80-column punch cards.  It is used to be sure, at 
the last moment, that the cards in the deck are in the order you say they are 
in.  If they are not in the order you say, you got a hard halt.


>2.how are indicators U0-U9,MR used.
   U1 through U9 are the labels for what used to be User Toggle Switches on the 
computer.  It was a way to send a simple instruction to a program at run-time.  
The switches were replaced with virtual switches, but they still do the same 
job.  A switch will stay in the position it is set for the rest of the user's 
session or until changed, regardless of what activities the user does.  An 
example might be: You decide that Switch-7 is the update switch in your 
programs.  So, as you write your programs you condition all updates to data on 
U7.   Then, in production you set user's profiles for Switch-7 on or off by 
whether or not the user can update data.  Primitive of course, but hey, 
switches are over 30 years old and still supported.

MR is for matching records.  It relies upon the cycle.  It is accurate, fast, 
and easy to understand and implement.  If you use MR real programmers will 
laugh at you; they prefer rolling their own logic.

>3.is there any way i can try out RPG programs using internet ie 
>downloading or etc.
   I wish there was.  Maybe someone will sell accounts for $10 a month, who 
knows.

>4.can a subfile be used to access data from different physical files if 
>so how can an update pgm work on different physical files. 
  Yes.  You need to know which fields are changed, and where the fields come 
from.  What I do is this: each subfile record has the fields in it for the 
unique keys of the physical files I am dealing with.  I mark the fields as 
hidden fields so the screen won't be all cluttered up.  Then, when I read the 
changed subfile records I know the unique key to each Update/Add file in the 
program and can easily get the correct record to modify.


-- 
-----------------------------------------------------------
boothm@ibm.net
Booth Martin
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