Re: read/chain/write/update with *input/*output/*all DS

[Rory Hewitt <rory.hewitt@xxxxxxxxx>]

Lim,

Another alternative would be initially load the data from CUSTL1 into an
array, which you could sort however you want and display in the subfile. If
(and only if) a user actually updates the data, you chain to the record
(using the customer number from the array element), check no other user has
changed it since it was loaded into the array, and update that record in
CUSTL1.

In this case, you only need to define a single LF, and instead of all the
CHAIN's, you simply do a LOOKUP (optionally defining the array as ASCEND and
sorting the array immediately before the LOOKUP to enable RPG to do a binary
search).

Not necessarily 'better', and probably not a possibility if there are more
than 32767 records in the file (max # of array elements) unless you want to
get creative with qsort/bsearch, but it avoids the specific problem you're
having...

Rory

On Tue, Aug 17, 2010 at 11:56 AM, hockchai Lim <
lim.hock-chai@xxxxxxxxxxxxxxx> wrote:

> ok.  I guess my OP is not stating my problem too clear.  Sorry about that.
> 2nd try:
>
> Let's assume that I've green screen app that allows user to pull up
> customer
> record in serveral different ways, by customer #, by Creditcard #, by
> SSN....
> I order to lookup the customer record base on whichever lookup method user
> used on the screen, I would need to have two or more customer master
> logical
> files (one for each lookup method) on F spec.  After using the proper
> logical file to lookup customer record, the program displays the customer
> record to the user, user then updates the info on the screen and press
> enter.  The RPG program then validates it and update the Customer record.
>
> If I don't use qualified result-field DS, then everything is business as
> usual.  Since fields in all those different logical files are global and
> there is only one set them, It does not matter which logical file the
> program uses to lookup the customer record.  The same set of fields are
> populated after a sucessful chain.  Again, since there is only one set of
> fields, I can freely use then without regard to which logical the program
> has used to chain.
>
> in this case, the RPG program would look like this:
>
> if customer# <> 0;
>  chain (customer#) CUSTL1;
> elseif creditcard# <> 0;
>  chain (creditcard) CUSTL2;
> elseif ssn <> 0;
>  chain (ssn) CUSTL3;
> . . .
> endif;
>
> ScreenField_CustName = CUSTNAM;
>
> exfmt mainScreen;
>
> CustNam = ScreenField_CustName;
>
> chain (CUST#) CUSTL0 tmpCUST;
> update CUSTL0;
>
>
> How/what would be the best way to handle above if I prefer to always use
> result-field DS when performing file IO opcode?