RE: Logical Files vs. Physical Keys

["Sims, Ken" <KSIMS@xxxxxxxxxxxxxxxx>]

Hi Mike -

>Date: Fri, 24 Mar 2000 12:00:55 -0500
>From: "Mike Cunningham" <MCUNNING@pct.edu>
>Subject: RE: Logical Files vs. Physical Keys
>
>Any coding design that relys on an abnormal termination for a unique key
>error instead of doing a SETLL to see if the key exists before writing a
>record  is just bad design technique

And any coding design that relies on just doing a SETLL is also bad design.
Though small, there is a window between the SETLL and the WRITE when another
job could add a record with the same key.

Use the SETLL to avoid logging unnecessary messages in the job log; but
still have the file coded UNIQUE and use duplicate key error checking to
close that little window.  Which brings us back to the original point ...
having the physical keyed and UNIQUE makes it a lot harder for someone to
remove the unique key checking.

Ken
Southern Wine and Spirits of Nevada, Inc.
Opinions expressed are my own and do not necessarily represent the views of
my employer or anyone in their right mind.

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