Leandro Guimarães Faria Corsetti Dutra wrote:
>Jan Hidders wrote:
>>Leandro Guimarães Faria Corsetti Dutra wrote:
>>>Jan Hidders wrote:
>>>>
>>>> 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.
>>
>> Where exactly in those articles do they claim that you cannot use FOL
>> to describe constraints in the ER model?
>
> No, they claim that ERDs can't represent all possible constraints.
Of course. (Do you think that the Relational Model can, by the way?) But I
said that you can use FOL to describe constraints in the ER model. So if you
extend the ER model with FOL (which is not very difficult) then you can
describe those constraints.
Received on Thu Oct 31 2002 - 16:33:31 CST
