Jean-Marc Orliaguet wrote:
(SellerURI, merchandiseURI, BuyerURI, "Sale Transaction")
Let's rewrite this relation to a prolog equivalent fact:
transaction(SellerURI, merchandiseURI, BuyerURI, "Sale Transaction").
There is no primary key in that relation. We could add one such as
TransactionURI for instance :
transaction(TransactionURI, SellerURI, merchandiseURI, BuyerURI, "Sale
In this case we could rewrite this fact without loss of information
using only binary relations/predicates by projecting it:
transactionType(transactionURI, "Sale Transaction").
This description is then equivalent and RDF friendly. However it
requires the introduction of a primary key which was implicit in the
first description and is much more verbose.
In the portletInPerspective example, one would similarly need to
introduce a primary key to be able to describe the same facts using
bianry relations only and thus being able to use a rdflib graph to store
and query the local/contextual porlets layouts.
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