Drupal exporter and Ontology question
Alexandre Passant
I've just updated Drupal exporter to reflect latest ontology specs
regarding Post properties.
Regarding the specs, there are 2 ways to define "topics" of a Post.
1) Use sioc:topic, type: Resource
2) Use sioc:subject, type: Literal
So, for a given topic, we could do both:
<sioc:topic rdfs:label="thinkpad"
rdf:resource="http://apassant.net/blog/tag/thinkpad"/> as in current
export API
or
<sioc:subject rdf:about="http://apassant.net/blog/tag/thinkpad"/>thinkpad</sioc:subject>
as I've done in Drupal API
Actually, and as discussed with Christoph on IRC, I think sioc:subject
should be used for (free) tagging, with rdf:about to link to the page
containing all the post with the same subject, and that we should keep
sioc:topic to link to SIOC concept or domain ontology resources.
That's what I've done so far with to distinguish tags free tags and
ontology concepts in posts indexing.
What others think about it ?
Alex.
Uldis Bojars
Regarding 'sioc:topic' and 'sioc:subject':
SIOC has 2 properties in order to express both between text keywords =
literals and tags/categories/keywords that can be expressed using a
URI. Using a URI (and sioc:topic) is preferred and in a majority of
cases a site already has some kind of URI for each tag/category.
About sioc:subject - it has the same meaning as dc:subject therefore
(as part of aligning SIOC with DC) we can drop this property and use
dc:subject instead.
> So, for a given topic, we could do both:
>
> <sioc:topic rdfs:label="thinkpad"
> rdf:resource="http://apassant.net/blog/tag/thinkpad"/> as in current
> export API
>
> or
>
> <sioc:subject rdf:about="http://apassant.net/blog/tag/thinkpad"/>thinkpad</sioc:subject>
> as I've done in Drupal API
Second RDF snippet is invalid - you may not use rdf:about with a
property.
> Actually, and as discussed with Christoph on IRC, I think sioc:subject
> should be used for (free) tagging, with rdf:about to link to the page
> containing all the post with the same subject, and that we should keep
> sioc:topic to link to SIOC concept or domain ontology resources.
> That's what I've done so far with to distinguish tags free tags and
> ontology concepts in posts indexing.
As we agreed on IRC let's use sioc:topic to link to a URI when we can.
And have dc:subject in our "arsenal" for cases when a URI can't be
figured out.
A more philosophical question: is there a need to distinguish between
free tags and ontology concepts? Free tags are like a dynamic and very
flat taxonomy and there is not much difference in how they are used.
This may be similar to our previous discussion about Posts and Comments
- the difference is technical, not so much conceptual.
Uldis