Re: Surrogate Key vs Production Key

From: Daniel Morgan <damorgan_at_x.washington.edu>
Date: Sun, 10 Oct 2004 11:09:20 -0700
Message-ID: <1097431844.507435@yasure>

Noons wrote:

> "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message news:<ck8k9q$127$1_at_titan.btinternet.com>...
>
>

>>This doesn't make your original suggestion any
>>more likely to be realistic. Manual data entry of child
>>rows normally requires at least an initial cross-check
>>against the existence of a parent.  Your "thousands"
>>of rows would probably require a typist to make the
>>same typing error thousands (or at least hundreds) of
>>times in a rows without noticing.  And if the data entry
>>was a consequence of acquiring the real value from a
>>real object this seems an unlikely chain of events.

>
>
> I am not proposing a theory. What I related are facts.
> Which I have witnessed first hand. A wrongly typed postcode
> can be used in thousands of related rows. For that, it gets
> pulled in from a dropdown list, it is not entered manually.
> Same goes for any other top-level hierarchical information: it
> is entered into the system once and gets used from dropdowns.
> Six months later someone realises that postcode 3133 should
> have been 3134. Bingo: maintenance nightmare with natural
> keys. Zero hassle with surrogate keys.

Good lord man you aren't using postal codes as keys are you?

Well of course not ... so what is the point of your example?

So lets try this ... how many times can you enter the single person Noons in the person table with a surrogate key? How many times with a natural key? Of course assuming one exists.

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

Received on Sun Oct 10 2004 - 13:09:20 CDT