Re: check for record changed between read/chain(n) and update

You don't need the unlock line assuming the HCLMMAS file's record format
is CLMMAS in the CHAIN(N)
before the unlock.

HTH,
Charles




> -----Original Message-----
> From: rpg400-l-bounces+wiltc=cintas.com@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces+wiltc=cintas.com@xxxxxxxxxxxx] On
> Behalf Of Gene Burns
> Sent: Tuesday, June 05, 2007 12:17 PM
> To: RPG programming on the AS400 / iSeries
> Subject: Re: check for record changed between read/chain(n) and update
>
> Thanks, Booth!
>
> I setup 2 data structures to start with:
>
> d savmstr e ds extname(hclmmas) prefix(o)
>
> d mstrDS ds likerec(clmmas)
>
> then I brought in the data:
>
> chain (cmyrin: cmycin) clmmas; // get
> data for pgm
> // ekb13 begin block
> chain(n) (cmyrin: cmycin) clmmas mstrDS; // load DS
> unlock hclmmas; // release lock
> savmstr = mstrDS;
> // ekb13 end block
>
> So now I have the data saved in a data structure, still have
> the fields available (no rewrite), and no lock on the file.
>
> Thanks everyone!
>
> On 6/5/07, Booth Martin <booth@xxxxxxxxxxxx> wrote:
> >
> > What I do is have three data structures named "Record",
> "OriginalRecord"
> > and "NewRecord", all defined like the record format. Then
> I prefix two
> > of the data structures as "O_" & "N_" Then, on the
> original read I
> > eval OriginalRecord = Record.
> > Then, later just before I do the locking read I move the
> Record (which
> > now has the new values) into NewRecord, If NewRecord =
> Original then
> > there are no proposed changes, so bail out.
> > Otherwise do the locking read and again compare the Record
> to Original
> > Record.
> > If the Original is *not* equal to the Record then there have been
> > changes at another workstation, do as is appropriate to the
> business
> > rules.
> > If the Original is equal to the Record then its is safe to make the
> > change, so eval Record = NewRecord and do the update.
> >
> > Seems to work fast and is really handy if you also are using
> > F5=Refresh (Record = OriginalRecord) to let the user undo
> changes and start over.
> >
> >
> >
> > Gene Burns wrote:
> > > I need to change a program to get a record from a file
> chain(n) and
> > > let
> > the
> > > user work with the data, go to other programs, return to the
> > > original calling program, etc., then if the user makes changes to
> > > the data I need
> > to
> > > check whether the record has changed before updating.
> > >
> > > Is there a better way to do this than bringing the data
> record into
> > > a
> > data
> > > structure chain(key) file DSname and then rewriting the entire
> > > program
> > to
> > > use the qualified field names from the DS?
> > >
> > > I am concerned that even if I do this, that the record could be
> > > updated
> > in
> > > between the chain to get the record into a DS for
> comparison to the
> > original
> > > DS and the actual update.
> > >
> > > Gene
> > >
> >
> > --
> > ---------------------------------
> > Booth Martin
> > http://www.Martinvt.com
> > ---------------------------------
> >
> > --
> > This is the RPG programming on the AS400 / iSeries
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> >
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