krislioe_at_gmail.com (xtanto) wrote in message news:<e1c9bd55.0410052139.2c139132_at_posting.google.com>...
> Hi Gurus,
>
> I have a transaction table having unique external document number. It
> can be assured that it is unique. It is a varchar2(30).
> This is a header-detail transaction.
>
> The options is :
> Whether I should use this unique external document table as PK ?
> (means I have also to store this value in Detail table)
> OR
> Should I create an ID based on Sequence as 'Surrogate' PK ?
>
> What is the cost/benefit ?
The biggest problem of not using surrogates is that you do not have
the control over used key values. In this particular case it's going
to be funny when you will get another external resource for these
documents with overlapping keys.
I'm recommending to use external keys only for world wide accepted
keys that are enforced by laws, compliance rules etc. (such as social
numbers, ZIP codes, ...), I would never use external key based just on
someone else design.
--
Dusan Bolek
http://www.db-support.com
Email: spambin_at_seznam.cz
Pls add "Not Guilty" to the subject, otherwise your email will face an
unpleasant end as SPAM.
Received on Wed Oct 06 2004 - 07:00:16 CDT
