Re: database design

In article <Z67t5.35$bU.82754_at_news.uswest.net>,   "Dan Guntermann" <guntermann_at_uswest.net> wrote:
> I find it interesting that the concept of "data independence" has not
 been
> brought up yet. Especially since it is a fundamental concept of the
> relational model. The whole point being that both the physical and
logical> structure of data in the database acts independently of any application. I
> believe that the whole point of the relational model is that a
 database
> should be designed without any application in mind, and thus should be
> designed separately

I agree, but I've been here long enough to know that to design a good database (the physical implementation of a data model), you'll need to have a solid knowledge of the usage of the data; the amount of rows and the access paths will have an important role in the "final decisions" when it comes to launching those create-statements (normalize yet optimize).
So far for data independency.
However, when it comes to designing the logical data model one should never ever let think about how the application (system) will be using its future implementation.
That is why I don't think that in the real world a tool which just generates a physical model from a conceptual model and a schema (the database) from that physical model will work. In most cases the DBA will need to perform some surgery at every stage to make the end-result (the database) as good as the application needs. Alas, even in the year 2000 changes in the access path might need changes in the database definition since physical IO still is the bottleneck when it comes to performance. The conceptual model only changes when the company changes.

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Before you buy. Received on Wed Sep 06 2000 - 09:07:59 CEST