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.
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