RE: the idea of unique primary keys to be a solution that hasoutl ived its usefulness?

Booth,

I'm really neither agreeing nor disagreeing.  I definitely think it all
deserves discussion.  However, we in IBM midrange think about database
design diferently that other parts of the world, and I think these
differences can cause unintended problems sometimes.

Unique primary keys are not what most of us use on the iSeries.  We use
unique compound keys, where the combination of many factors (keys) work
together to define a unique row.  Unique primary keys are a single field
that describes a unique row.  These are commonly implemented as UUIDs, or
possibly as auto-incrementing value for such things as order number and
whatnot...

You are right that we commonly have to "force" uniqueness for a file when
someone has not followed the rules properly, or the application design has
changed.  The old "sequence#" subkey is the most common fix that I've seen,
but this can cause some nasty surprises.

Personally, I like the use of compound keys, but it's one of those YMMV
issues.  I think that most shops fail to use "Unique" keyword in DDS,
because they don't like trapping for I/O errors. 

Eric DeLong
Sally Beauty Company
MIS-Project Manager (BSG)
940-898-7863 or ext. 1863



-----Original Message-----
From: Booth Martin [mailto:Booth@xxxxxxxxxxxx]
Sent: Monday, November 17, 2003 2:54 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: RE: the idea of unique primary keys to be a solution that
hasoutlived its usefulness?


I am curious if i am alone on my thoughts about unique keys.  If there is a
very loud silence we will know that unique keys is the answer.  Is there
other ways to have various addresses without using defined record types as
part of the key. 

*vbg*  (I have no delusions abut my weird ideas.) 
 
 
 
---------------------------------------------------------
Booth Martin   http://www.MartinVT.com
Booth@xxxxxxxxxxxx
---------------------------------------------------------
 
-------Original Message-------
 
From: RPG programming on the AS400 / iSeries
Date: 11/17/03 14:12:28
To: 'RPG programming on the AS400 / iSeries'
Subject: RE: the idea of unique primary keys to be a solution that
hasoutlived its usefulness?
 
In this case, I would have a separate file for addresses and use a type to
differentiate them.  We are, in fact, getting ready to develop a new
customer tracking database using a similar model.
 
Donald R. Fisher, III
Project Manager
Roomstore Furniture Company
(804) 784-7600 extension 2124
DFisher@xxxxxxxxxxxxx
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