Re: foundations of relational theory?

"Anthony W. Youngman" <thewolery_at_nospam.demon.co.uk> wrote in message news:gHbL4mIk0Gn$EwYg_at_thewolery.demon.co.uk...
> >Agility is enhanced by the fact that some of the more complex
> >possibilities for data models, such as many-to-many relationships,
> >are simply excluded.
>
> NOT AT ALL. many-to-many is easy. You need a table specifically to store
> foreign-key pairs, we just store the foreign keys directly with the
> entity (because we can shove a list of foreign keys into what relational
> would call a "cell"). Each entity manages its own one-to-many list (the
> LHS *must* be one, because it's an individual entity :-)

That's not a many:many relationship, though; that's a pair of one:many relationships. IIUC, you don't have a way to automatically manage keeping them in sync. It's also redundant.

Marshall Received on Mon Oct 27 2003 - 09:27:34 CET