Re: database design method
Date: Sun, 17 Nov 2002 22:39:17 GMT
Message-ID: <H5qs9F.54p_at_news.boeing.com>
Thanks,
Dan
"Jan Hidders" <hidders_at_REMOVE.THIS.uia.ua.ac.be> wrote in message
news:3dd59681$1_at_news.uia.ac.be...
> Lauri Pietarinen wrote:
> >Jan Hidders wrote:
> >
[snip]
>
> Yes, but the object identifier as pointer is not the type of object
> identifer I (and the article I mentioned) was talking about. What I meant
> could also be called "abstract value" and is in some sense the theoretical
> clean version of surrogate identifiers. The big difference with surrogate
> identifiers is that the user can never get to see their value and the only
> operation that is defined for them is equality. Such a restricted type may
> seem a bit strange and not very useful at first sight but it makes the
life
> of the DBMS easier (for example the DBMS can reuse identifiers that are no
> longer used) and allows the user to define views and queries in which new
> identifiers are generated without using some clever arithmetic to generate
> new surrogate identifiers. In fact, if such object identifiers are
possible
> (including special operators to generate them) IMO the good old flat
> relational model would be all we need.
>
Received on Sun Nov 17 2002 - 23:39:17 CET