Re: database design method

Jan Hidders wrote:

> Leandro Guimarães Faria Corsetti Dutra wrote:
>

>> Jan.Hidders wrote:
>> 
>>> Sure it has. It can use the same language that you can use for
>>> the relational model: 1st order logic.
>> 
>> Now I want to see it.  References, please.  You may want to be 
>> informed of articles against your view in http://dbdebunk.com./,
>> for instance.

        No, but it is a nice reference site and eye-opener.

> The fact that you can use FOL to describe
> constraints in the ER model is so plainly obvious to people who know
> about logic and ER models that no serious researcher would write an
> article about that.

        What about Fabian Pascal as "serious"? What about http://dbdebunk.com./fp4a.htm as an article? Or take Date and http://dbdebunk.com/kimball1.htm.

> If you think there is an inherent problem there then I suggest you
> share it with us and I will be happy to explain why it isn't a
> problem. :-)

        OK. How do you express non-RI constraints? How one does express each domain, attribute, relation and database integrity constraints? Or in a different taxiology, take transition constraints, how would ERDs represent them? I'm not saying you mightn't have a partial answer, but I very much doubt you could give (or point to) a complete answer.

> But what makes you think you need set theory to specify constraints?

        Nothing. But you need set theory to come up with the idea of relations in the first place, and all its attendant operations, and to have what to create constraints on.

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