xml-dev - Re: data smushing

[Ken MacLeod <ken@bitsko.slc.ut.us>]

David Megginson <david@megginson.com> writes:

> Outside the research lab, #2 is extremely difficult.  For #1,
> however, all we have to do is extend the (oversimplified version of
> the) RDF logical model to include one more member:
> 
>   {predicate, subject, object, source}
> 
> where source is a URI representing the source of the information
> (probably, but not necessarily, the URL of an RDF document; it could
> also be a URI representing a news wire, for example).  Now, query
> operations, searches, etc. can take into account where the
> information came from, and can distinguish, say, two "name"
> properties provided by the same source from two "name" properties
> provided by two different sources.

I'm no RDF guru, but in discussions I've read I thought "reification"
was intended for this purpose, isn't it?

So instead of ever extending the RDF tuple:

  {predicate, subject, object, source}

One uses reification to further describe a statement:

  {predicate, subject, object}   ; original statement
  {'source', {predicate, subject, object}, source}

Where the original statement becomes the subject for further
statements.

Taking your longer example:

  {predicate, subject, subjectType, object, objectType, lang, source}

Would be (forgiving me making up my own shorthand here):

  orig-stmt = reify({predicate, subject, object})

  {'subjectType', orig-stmt, subjectType}
  {'objectType', orig-stmt, objectType}
  {'lang', orig-stmt, lang}
  {'source', orig-stmt, source}

Again, I'm no RDF expert though.

  -- Ken