[ZODB-Dev] Re: [Zope3-dev] PROPOSAL: ZODB Relationships

[Roché Compaan]

On Fri, 09 May 2003 10:38:51 +0100
Chris Withers <chrisw at nipltd.com> wrote:

> Roché Compaan wrote:
> > What we have at the moment is a graph and strictly speaking a graph has
> > no direction in its edges (maybe you meant directed graph). As far as I
> > can see graphs are possible, hierarchies are not. Can't one just use
> > containment to represent hierarchies? If one can what other use cases
> > are there for directionality in associations?
> 
> You can only use containment once ;-)
> 
> I can't think of any good examples, but if you wanted to express more
> than one relationship that wasn't direction-agnostic, then you
> couldn't use containment for both of them.
> 

Maybe I wasn't too clear. If you want to represent a hierarchy you won't
use Relationships, you'll use a folder tree for example. The proposal
doesn't address hierarchies because it is not a problem and is already
quite easy to do in the ZODB whereas relationships are not.

-- 
Roché Compaan
Upfront Systems                 http://www.upfrontsystems.co.za