Re: One to One Relationship

"Noons" <wizofoz2k_at_yahoo.com.au.nospam> wrote in message news:Xns9344C9CD25179Tokenthis_at_210.49.20.254...
> Following up on Paul Brewer, 20 Mar 2003:
>
> >
> > I don't disagree with any of this, nor with other examples posted, but
> > these are *physical* considerations.
>
> Sure, but subtyping isn't. It can serve a very specific
> logical purpose. I think the old books on Case Designer
> had a good description of where, but I can't find mine
> anywhere!
>
>
> > Earlier in this thread, I suggested that they are *logically* the same
> > table, and recommended that OP do the logical design before moving on to
> > physical considerations.
>
>
> Absolutely! In fact, my feeling is that the OP was talking
> about a true 1:M case, not 1:1 at all. He was just getting
> mixed up.
>
>
> >
> > I concede, however, that I may have put it somewhat abruptly.
>
> Hey! No problems with that, as far as I'm concerned! :)
> The reason I entered the thread is that I felt true 1:1
> was being set aside as a "no-no". Which I feel is not the
> case: most subtypes are 1:1, if not all. So, I gave a few
> examples of where it is useful.

Hey, that is the same reason I entered this thread. I believe that 1:1 is also applicable in relational database theory and so I wanted to give an example that I believe would highlite this issue. If someone could work out a way of not having 1:1 then I'm all for it, but I think that this isn't the case. There are many many examples of needing 1:1 and it is better to lock it down on the database side of things rather than leave it to front end developers. You need to enforce constraints so that all of your data is good.

Aside from that, are the same Nuno from the optus newsgroup?

>
> --
> Cheers
> Nuno Souto
> wizofoz2k_at_yahoo.com.au.nospam
Received on Thu Mar 20 2003 - 18:32:24 CST