Re: ER Model - different answers for different join paths

>
> If we assume that ER is about the structure of data and not its use (as
> Chen says) and if you believe that physical database design is about
> applying usage to the static data model, then I beleive DM is database
> design and not data modeling.

I believe that Kimball could agree with you. If I interpret Kimball correctly, he sees ER as emphasizing the relationships between data. DM is a style of design used (quite effectively) to get performance and to make it easy for query tools to generate business queries in SQL. (In this sense, I interpret Kimball as being a pragmatist.)

> But Kimball seems to position DM against ER
> which (I am right) does not make sense at all. Does this make any sense?
>

Kimball positions DM (design) against data warehouse designs done in a typical OLTP/ER-like design.

If you replace "ER" with "ER style design" and "DM" with "Dimensional Design" in Kimball's articles then it is valid to compare the benefits of "ER style design" with "Dimensional Design."

-Clark Received on Wed Aug 13 1997 - 00:00:00 CDT