Re: An object-oriented network DBMS from relational DBMS point of view

On Mar 12, 11:01 am, "Dmitry Shuklin" <shuk..._at_bk.ru> wrote:
> 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.

> 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, independent
of any problem context. Many problems admit to many different techniques
for solving them. Simply heaping together features from OOPLs and the relational model will not get you good design. There are advantages
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.

Marshall Received on Mon Mar 12 2007 - 19:56:45 CET