"Jay Way" <jayway@myrealbox.com> wrote in message
news:56cc6b5c-bda2-4fba-a421-8e2994c9321f@a23g2000hsc.googlegroups.com...
> I'm a beginner at DW and BI. I'm posting to this NG because my current
> (and first) data warehouse project is using SQL Server 2005 and my
> question is regarding the Kimball book "The Microsoft Data Warehouse
> Toolkit" (2006).
>
> The authors are saying to store in your dimension tables the natural-
> key counterpart to the primary identity key, in the enterprise data
> model, so that you can match on it when looking up surrogate keys
> during fact table load (page 267). But this seems like a pollution of
> the dimensional model with ETL-support data if the natural keys were
> not specified in the data model by a business requirement.
>
> Am I reading this wrong? Thanks for any reply.
>
> -- Josh


You will always have a potential natural key in your tables if you eliminate
duplicate rows properly in your ETL process. It wouldn't make much sense as
a business requirement to have rows with different surrogate keys that were
duplicated on all other columns.

--
David Portas