Re: Surrogate Key vs Production Key

From: Daniel Morgan <damorgan_at_x.washington.edu>
Date: Wed, 13 Oct 2004 19:45:13 -0700
Message-ID: <1097721999.408108@yasure>

Galen Boyer wrote:

> On Mon, 11 Oct 2004, damorgan_at_x.washington.edu wrote:
>

>>Galen Boyer wrote:
>>
>>>What does one do when the "natural keys" are actually
>>>different based on the source?  Maybe someone needs to define
>>>a "natural key".  Seems to me, it is a key that some other
>>>system has already defined.
>>
>>The natural key is well defined by the work done by Date and
>>Codd.  That which uniquely defines a record in one set does not
>>necessarily define a unique record in another set.

>
>
> So, what does one do when there are multiple sources of data.
> Suppose you are storing loans for customers who want to login to
> your analytic application and analyze their loans. One
> customer's representation of the loan is a string, one is a
> number and one has a two-part key. Whats the "natural key"?

Then by definition you don't have a natural key.

What is a natural key in one system may not be in another. To try to treat it otherwise is tortured logic.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)

Received on Wed Oct 13 2004 - 21:45:13 CDT