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Re: Database Design

From: David Cressey <>
Date: Sat, 15 Sep 2001 20:01:42 GMT
Message-ID: <GsOo7.31935$>


I don't want to discourage you from pursuing the design you are following. It may well be that your design suits your needs very well.

I will caution you in one regard, however.

One of the major advantages of the widespread relational DBMS products is that, once someone learns the structure of the data dictionary, that person can now learn the logical structure of any schema built on that platform, without having to go to any other documentation. In Oracle, for example, the Data Dictionary will often reveal to a person well versed in Oracle exactly what the schema looks like.

Often that's enough information to begin cranking useful reports and analyses, with no more underlying documentation.

But, when the trick you've outlined is implemented, there's an additional layer, the layer you've designed, that the person who is an "Oracle expert" but doesn't know your design, has to decode before being productive.

As long as you keep it to a single table, as you have, an old hand shouldn't take more than a couple of hours to figure out how you coded the metadata. But I've seen cases where metadata was stored in user tables, so as to permit altering the schema with DML and not with DDL, and where literally dozens of user tables were used to store the metadata. And, of course, there was no documentation. And, of course, the application came with no management reports, because that's "coming with the next release" of the application.

In a case like that, it can literally take weeks of detective work to discover something about the structure of the data that should have taken minutes. Of course, how tough it is for someone else to make productive use of the data may not be your concern. But if you want to "do the right thing", you'll make sure you don't dig too deep a hole for the person who has to turn your data into information that can be used for decision support.

    David Cressey
"H" <> wrote in message

> Hi,
> I want to design a database keeps track of customers for example
> a customer's age, sex, state etc. However I don't
> want the table fixed.
Received on Sat Sep 15 2001 - 15:01:42 CDT

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