Re: Myltiple surrogate keys in one table!
From: David Cressey <david_at_dcressey.com>
Date: Sat, 14 Jul 2001 16:40:37 GMT
Message-ID: <9C_37.34$x4.2007_at_petpeeve.ziplink.net>
Date: Sat, 14 Jul 2001 16:40:37 GMT
Message-ID: <9C_37.34$x4.2007_at_petpeeve.ziplink.net>
Joe,
Ralph Kimball uses the merger of two companies as one reason to use
surrogate keys for dimension tables in a warehouse, even when the
operational system is getting along just fine with primary keys drawn from
the subject matter.
Unless, I'm misreading Kimball, the idea is that, after the merger, the
warehoused records from each of the two source companies will have two
columns for the "original operational primary key" from each source, with
a NULL in the column that doesn't apply, and a single surrogate key for the
That way, the warehouse can survive the merger more readily.
--
Regards,
David Cressey
www.dcressey.com
"--CELKO--" <JOE.CELKO_at_TRILOGY.COM> wrote in message
news:33254b33.0107121048.6879a40_at_posting.google.com...
> >> table with more than one surrogate key ... I'm unable to come up
> with any reasonable justification for 2 surrogate keys in one table.
> <<
>
> The one case I remember was two different catalog numbering systems
> when two companies in the same industry merged...
Received on Sat Jul 14 2001 - 18:40:37 CEST