Ours as well-- IIRC, in the early S/38 / AS/400 days the thought was that since a Physical File consisted of the data portion and an index, you were out of luck if the index got corrupted-- you'd lose your master file!

Of course, in most cases you could CPYF FROMRCD(1) to read by RRN instead of by key, and salvage your data.

The problem was overblown; but some applications...


Paul E Musselman
PaulMmn@xxxxxxxxxxxxx


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Rob Berendt
Sent: Monday, August 28, 2017 1:58 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Subject: RE: Database design question

*SNIP*

That being said however, our ERP package has no primary nor unique keys on
the underlying table. They have a key on some of the logicals but do not
specify unique. In theory you could have duplicate keys but their
programming logic doesn't permit it (from transactions done within the
programming logic).

I think the thing was 40 years ago there was certain corruption which was
easier to recover from if your table did not have any keys on it. Don't
laugh, I think that is really the reason.

*SNIP*

This thread ...

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