Re: Database design
Date: Tue, 21 Feb 2006 11:59:14 +0100
Message-ID: <43faf28b$1_at_news.fhg.de>
Mark Johnson schrieb:
> Alexandr Savinov <spam_at_conceptoriented.com> wrote:
>
>>> I agree. But so what? I could have an attribute of type "tree".
>
>> Then the question is who will manage its content and be responsible for >> integrity, consistency and other issues? If it is the database then it >> could be qualified as a tree-aware database. If it is you then the >> database is of non-tree type (even if it stores trees). Thus it does not >> matter what kind of data a database stores. It is important what portion >> of its semantics it can understand and manage.
>
> That was something Codd hoped to accomplish, as I understand it,
> removing the data from the program, as it were. Breaking out
> processes. In that way, it can simplify matters, protect some data
> integrity, and the rest, and seem only overkill for particularly small
> or trivial projects.
>
>
> http://conceptoriented.com
>
> As I understand it, aren't your 'class operators' much like level/join
> operator of XSLT? Alice.Bob.Walker implies some routine/mechanism to
> tie Alice to Bob, and then Bob to Walker, but which will not tie Alice
> to Walker directly? It would essentially be an alias for Connect By?
I do not know if it relates (directly) to XSLT and where did you see 'class operators'? The idea is that a model should be aware of the data item connections; it should manage links - not items. The price for that is a concrete structure the model must obey. More specifically, we bring a order into a set of data elements. And this order is the most important thing because it determines everything including data semantics. An element is positioned among other elements and this position determines what does it mean. If we change it then the data element changes its meaning accordingly. So it is not important what is inside - it is important how this element is positioned among other elements. Each element has a number of superelements and a number of subelements (normally these are concepts and data items). If you further describe it formally then you get the concept-oriented data model.
-- http://conceptoriented.comReceived on Tue Feb 21 2006 - 11:59:14 CET