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Bingo - we have a winner. Vanna, show him what he's won .... :-) On Sat, 20 Sep 1997, Kahn, David wrote: > Let me throw out a design strategy for discussion. (It's not an original > idea, by the way; it goes back to S/38 days.) > > In the source of all logical files, do not simply define the record > format but explicitly code the fields required, even if all fields are > required. Disallow direct use of physical files by programs; some people > think this is good practice in any case. > > Now, if you need to add a field to a physical file, and this field will > only be used in a few places, you can create a new logical containing > that field and use that logical in those places. The new field will not > appear in the existing logicals so the member format levels will not > change, so no need ever to use LVLCHK(*NO). The old programs will not > see the new field and it will not matter, even if the field is added > somewhere other than the end of the record. > > The extra workload of having to specify the logical file fields is not > that great, and it supports the idea that logical files are working > views of the database while the physicals are it's implementation. It > also encourages designers to think carefully about what needs to be in > each logical and not include fields that are not required. > > Comments? Objections? What do you think? > > Dave Kahn - TCO, Tengiz, Kazakstan > ========= > > e-mail: kahn@tengizchevroil.com (until September 30th) > dkahn@cix.compulink.co.uk (from October 1st) > > +--- > | This is the Midrange System Mailing List! > | To submit a new message, send your mail to "MIDRANGE-L@midrange.com". > | To unsubscribe from this list send email to MAJORDOMO@midrange.com > | and specify 'unsubscribe MIDRANGE-L' in the body of your message. > | Questions should be directed to the list owner/operator: david@midrange.com > +--- > umidr > +--- | This is the Midrange System Mailing List! | To submit a new message, send your mail to "MIDRANGE-L@midrange.com". | To unsubscribe from this list send email to MAJORDOMO@midrange.com | and specify 'unsubscribe MIDRANGE-L' in the body of your message. | Questions should be directed to the list owner/operator: david@midrange.com +---
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