RE: Update or delete without prior input operation

Thanks Scott, I realize I had several errors at play....
 

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of Scott Klement
Sent: Wednesday, May 10, 2006 1:45 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: Update or delete without prior input operation

Douglas,

> C     DVNDNO        CHAIN     PAYABLES
> C                   DOW       NOT %EOF

CHAIN does not set %EOF!!

CHAIN does not set %EOF on if no record is found.  So this code is
incorrect.  This loop won't even be entered if the previous READ or READE
operation hit the end of file.  Even if the CHAIN succeeds, it will never
enter the loop.  Furthermore, if the CHAIN fails, it'll still enter the loop
because CHAIN doesn't set %EOF!

You need to either do this:

   C     DVNDNO        SETLL     PAYABLES
   C     DVNDNO        READE     PAYABLES
   C                   DOW       NOT %EOF

Or this:

   C    DVNDNO         CHAIN     PAYABLES
   C                   IF        %FOUND
   C                   DOW       NOT %EOF


> C                   READE     PAYABLES

Here you're reading a file that you just CHAINed to.  That means, you
skipped a record -- the one you read with CHAIN a moment ago will never be
processed.


> C                   IF        DREFNO = PREFNO
> C                   DELETE    PAYABLES
> C                   UPDATE    PAYABLES
> C                   ELSE

Here you've just deleted a record.  That record is no longer there!  Now
you're trying to update it?  How can you update it, if it's no longer there?

Even if you put the UPDATE before the DELETE, it wouldn't work because you'd
release your record lock the moment you update it, so the delete would fail.

Not to mention that the whole idea of deleting a record you just updated
makes no sense.  Why update something you no longer want?


> I am chaining to the file with no problem and I need to stay within the
key
> (which is why I am using the reade), I am checking for a specific refno
and
> if I find it I need to delete it, but the system is complaining that I
have
> not performed an input operation....I would have thought the reade
performed
> that, what is the proper way to handle this?

That's because you did a DELETE after the READE.   When you try to update 
it, you'll get the "need an input operation" error because you have to 
read a different record before updating it.  As soon as you do an update 
or delete, you lose the record lock, and you have to read again before 
issuing the next update or delete.

Not to mention that it makes absolutely no sense to delete a record and 
then try to update it.  OR update a record and then delete it.  If you 
don't want the record, just delete it.  No need to do an update.