Re: Program design to minimize record locks

[Pete Helgren <Pete@xxxxxxxxxx>]

That is what I thought but I came up dry last night (too late I guess) I 
had tried a search on record lock but I should have sorted by date.  
There is a thread on June 5th that has to do with "check for record 
changed between read/chain(n) and update" that I am looking at now.

Thanks


Alan Shore wrote:
> Morning Pete
> if my memory is correct (not a sure thing now-a-days) but I'm sure there
> was a similar discussion not too long ago.
> You may want to check the archives.
>
>
>
> Alan Shore
>
> NBTY, Inc
> (631) 244-2000 ext. 5019
> AShore@xxxxxxxx
> "If you're going through Hell, keep going" - Winston Churchill
>
>
>                                                                            
>              Pete Helgren                                                  
>              <Pete@xxxxxxxxxx>                                             
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>              07/19/2007 09:58                                      Subject 
>              AM                        Program design to minimize record   
>                                        locks                               
>                                                                            
>              Please respond to                                             
>               RPG programming                                              
>               on the AS400 /                                               
>                   iSeries                                                  
>              <rpg400-l@midrang                                             
>                   e.com>                                                   
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>
>
>
> I have a change I need to make to a program that someone else had
> written.  The program logic for data I/O is in a /Copy member so that
> all programs using the logic are affected by a current "design flaw" in
> the program which READs the record and locks it until the screen is
> exited and the record is updated.  The record lock causes problems
> elsewhere.
>
> So, without making too many changes and breaking something, I figure I
> should be able to:
>
> 1.   READ the record (with no lock)
> 2.   Present the data to the screen
> 3.   Edit the data as usual
> 4.   READ the record again with lock for update
> 5.   Update the record releasing the lock.
>
> This is standard stuff, but I think I need a "intermediate" storage step
> to hold the initially read record, yes?  All of the RPG programs I have
> had experience with in the past have "direct" read/write IO with file
> record fields mapping to screen data fields using identical names.  In
> this revision, I think I can't do that since the second read of data
> would overlay existing fields with the same name.  So, I think I need to
> use a data structure to temporarily hold the original data while it is
> edited and verified.
>
> So, what is the simplest approach to reading the data file record,
> moving it into a DS, and then moving it out of the DS and back into the
> data file after being re-read?  And yes, I know that I'd have to check
> to make sure the record hadn't been updated during the time it was
> originally read and later updated.  I poked around for some examples
> last night and couldn't find anything I could use (immediately).  I'd
> like to avoid having to go back to each program that uses this /Copy
> member to make changes.  I'd like to only change the /Copy member if
> possible.
>
> Am I making any sense? Ideas?
>
> Thanks,
>
> Pete
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