[Zope3-dev] Re: [DRAFT] local portlets and perspectives

[Olivier Grisel]

Jean-Marc Orliaguet wrote:

> If you use a primary key to collect all the dyadic relations into a
> unique relation, then you have implicitly created a triadic relation
> (identified by the key), except that you also explicitly enumerate the
> underlying relations. So in the end you'll have to store: the primary
> key + 3 dyadic relations between 6 elements.

Yes, I was just saying that is possible to use only binary relations 
throutgh projections on a pure expressive power viewpoint by using 
theprimary key trick. In practice, this might seriously impact the 
perfomance of the data model since it implies a lot of join operations 
where a single select should be sufficient.

Furthermore, using binary projections instead of n-ary predicates make 
it much harder to a human to quickly understand the model.

Regards,

--
Olivier