Re: I/O routines in HLL

[Alan Campin <alan0307d@xxxxxxxxx>]

If we consider your subroutine(I hope you mean procedure) to be a
black box with a known set of inputs and a known set of outputs then
it would return only the records that you need. How the black box gets
the records should be hidden.

My basic rule is to push selection as much as possible to the
database. I do this by using SQL and letting the where clause or joins
to select only the records I need.

On Thu, Jun 7, 2012 at 8:43 AM, Stone, Joel <Joel.Stone@xxxxxxxxxx> wrote:
> In an HLL on Iseries (RPG or COBOL or other) is there a "best practices" method to build an I/O subroutine?
>
> For example to read a customer record, should the i/o routine contain ONLY a read, with any positioning/accept/reject logic outside the i/o routine?
>
> Or should the i/o routine be a black box which returns ONLY records that the program is interested in processing?
>
> Or is either approach equally accepted?
>
> Or a better approach?
>
> This would be AFTER an SQL or opnqryf or LF does its own filtering of the cust file.
>
>
>
> Also, is a priming read widely used to start sequential processing of a file, or is there a better method?
>
> (at my current job, priming reads are avoided, but that seems to add lots of complexity and layers - but maybe its just that Im not used to it)
>
>
> I know these are basic q's, but my new job is challenging stuff I thought was standard!
>
> Thanks!
>
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