Re: One-To-One Relationships

From: David Cressey <>
Date: Tue, 30 Oct 2007 14:26:44 GMT
Message-ID: <EaHVi.6368$8R1.904_at_trndny02>

"Phil Reynolds" <> wrote in message news:CGzVi.2012$
> One thing that's not clear to me is when it's appropriate to create a
> one-to-one relationship. I mean, in some cases it's obvious, if there's a
> set of data that wouldn't always apply; then you'd want to create that set
> of fields in a separate table with a one-to-one relationship. But in what
> other cases? After the number of fields in a table is greater than X?
> I'm just curious about what thoughts/theories/ideas people have about
> one-to-one relationships, because that's something that's never been
> entirely clear to me.

I think that a relationship is something you discover, not something you create. Are you talking about creating two tables where there is a one-to-one relationship between rows in table A and rows in table B? If so, I think what you have created is not the relationship as such, but a way of representing it in the database.

I hope this isn't too nit picky. I think the distinction between what you discover via analysis and what you create during implementation (following design) is very fundamental, and needs to be kept clear in all our discussions. Received on Tue Oct 30 2007 - 15:26:44 CET

Original text of this message