[AccessD] OT: The Great Primary Debate

IMO the PK shouldn't be meaningful, and shouldn't be used in any
calculations at all, so it shouldn't matter if its perfectly sequential or
not.

It's just there to uniquely identify records and used internally in
relationships.  An Autonumber PK fits the bill perfectly in Access, just as
an Identity integer field in SQL Server does.  Because its meaningless it
will never need to be changed and hence won't cause the problems that would
occur when using a natural key.

My 2 cents...  I never really understand what the arguments about, but
hey... 'whatever floats your boat'


-----Original Message-----
From: Stuart McLachlan [mailto:stuart at lexacorp.com.pg] 
Sent: Tuesday, 8 June 2004 9:07 AM
To: Access Developers discussion and problem solving
Subject: RE: [AccessD] OT: The Great Primary Debate

On 7 Jun 2004 at 13:27, Ken Ismert wrote:

> 
> 3. That's why I said auto-generated! This is where relying on a ANPK can
> cause you problems: you can't extend the table without ruining your
> calculations.
>

> For regular, sequential data (no interruptions) with a single field
natural
> key, or any data where a unique key can be mathematically calculated (as
> above), you can make an argument that ANPK is redundant, and can actually
> make the data more difficult to work with. This is where intent of the
data,
> and your data modeling style, plays the deciding role in your PK choice.
> 

In your data dimension table example, you are creating a meaningful field 
SequentialDateNumber (which you are calling ID) and are using it in data 
calculations.  

Thr real question in this situation is not whether you use this natural key
as 
a PK, but whether you have a PK in the table at all - which comes down to
the 
sub-debate about "what is a PK and what is it used for" :-)

















 
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Lexacorp Ltd
http://www.lexacorp.com.pg
Information Technology Consultancy, Software Development,System Support.



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