Re: An object-oriented network DBMS from relational DBMS point of view
Date: Mon, 12 Mar 2007 20:40:50 GMT
>>Hello >> >>>Every relation, by definition, has a set of attributes >>>whose values are unique, and which can therefore >>>be used in relational expressions to uniquely identify >>>a row. That's all you'd get out of a pointer. Further, >>>by requiring the unnecessary pointer, you constrain >>>implementations unnecessarily. >> >>But when I lose pointers I lose instance identity.
> Yes. One of the biggest advantages of excluding pointers
> from the model is that you lose instance identity, and all the
> complexity that comes with it. This is particularly desirable
> in a distributed context.
Instances of what, though? That is the question.
>>So It is impossible >>or very dificult for some table to be a self row. It is not a deal for >>me. >>Also I lose possibility for some row to be contained by many tables.
> These are just further consequences of the lack of instance identity.
> Also, I note that the things you're describing are features,
> of any problem context. Many problems admit to many different
> for solving them. Simply heaping together features from OOPLs and
> the relational model will not get you good design. There are
> in learning how best to use each techinque on its own merits. Once
> you have mastered that, you are in a much better position to consider
> how two models might be integrated, or even whether that would be
> a good idea.
One has to start at a very basic level asking why a feature exists in the first place. Received on Mon Mar 12 2007 - 21:40:50 CET