Re: Auto Increment

[Miles Thompson <milesthompson@ns.sympatico.ca>]

I would say that generally it's a good thing as it provides a unique key 
for each record. (I believe one of Codd & Dates's 12 rules for a relational 
database was that each record had to be uniquely identifiable, or something 
like that.)

Is it necessary? No, not really, and does impose a minor performance hit.

I generally use auto-incremented primary keys on tables where there are 
definite parent-child relationships. These keys can be used in the 
background avoiding any future complications where a client decides to 
redefine the serial number or similar value often used as primary key. Thus 
you are pretty-well protected against  changes to data fields, whihc means 
logic isn't broken, etc.

For lookup tables and the like I don't bother with auto-incremented keys.

Regards, and I hope this helps - Miles Thompson

At 11:38 PM 5/9/2003 +0100, shaun wrote:
> Hi,
>
> I seem to be putting an auto increment id field in all my tables, is this a
> bad thing? If so when should and shouldn't they be used?
>
> Thanks for your help
>
>
>
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