Re: problem using identity column as primary key
From: Joe Celko (joe.celko_at_northface.edu)
Date: 02/24/04
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Date: Tue, 24 Feb 2004 08:55:32 -0800
>> Identity is a great way of generating a primary key ... as the only
purpose of the PK is to have a unique value. <<
You are dangerous.
1) It cannot generate a key by definition. It is the PHYSICAL state of
the hardware that holds your database at a particular point in time.
2) The purpose of any key is to uniquely identify the entities in the
data model in a way that can be verified in the reality the model
represents. Uniqueness is necessary but not sufficient.
3) It is not even self-validating since there is no check digit or
syntax. That makes it lousy as just a unique number, since it has a
high error rate.
--CELKO--
===========================
Please post DDL, so that people do not have to guess what the keys,
constraints, Declarative Referential Integrity, datatypes, etc. in your
schema are.
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