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
---------------------------------

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