Re: dbdebunk 'Quote of Week' comment

"Alexandr Savinov" <spam_at_conceptoriented.com> wrote in message news:430efd5d$1_at_news.fhg.de...
> x schrieb:
> > This means that there must be a one to one mapping between the generated
key
> > and some key with a meaning for the end user. Therefore that meaningless
> > primary key is a pointer. But one of the goals of the relational model
is to
> > eliminate pointers from the data model.

> What is the difference between meaningless and meaningful pointer?

If the key is meaningful for the end-user, it is not a pointer.

> I think the model itself does not know anything about the meaning of the
> pointers/keys it uses. In this sense the question about the meaning of
> pointers/keys relates to data modeling in general rather than to the RM.

> In other words, the question is if we should choose meaningful or
> meaningless identifiers for our entites.

If they are meaningless, they are not identifiers.

> > Other goal is to give the end user direct access to data.

> Any access is indirect (by definition). By direct access we normally
> mean some lower level mechanism of access w.r.t. this level.
> (Absolutely) direct access does not exist just like instant interaction
> does not exist. Possibly you mean an illusion of direct access like in
> OOP where we manipulate object like if they were directly accessible.

Direct access as in access to data by standard tools, not by specialized applications. Received on Mon Aug 29 2005 - 09:09:44 CEST