Kurt J wrote:
Hi Robert,
Thanks for your detailed response. I've been successful in loading
rdf into virtuoso and the sparql features seem to work great. They
are publicly available at http://dbtune.org/cmn/sparql
In fact, with the help of Kingsley, Hugh, and the list, i've managed
to get dereferencable uris straight out of the sparql store using
virtuoso's url re-write tools.
So my basic goal is to follow the dbpedia-style linked data method
using the resource-data-page style. For example,
http://dbtune.org/cmn/resource/WAGN derefs to
http://dbtune.org/cmn/data/WAGN if you accept rdf.xml. then
http://dbtune.org/cmn/data/WAGN makes a describe sparql query to
output the appropriate rdf describing what is known about
http://dbtune.org/resource/WAGN. All this works lovely. Now i want
to server HTML versions for humans at http://dbtune.org/page/WAGN. I
thought i understood using /about/html was an appropriate way to do
this. however it would not work for me. the best i could get was
info about xsd style sheets.
if i understood Kingsley's email, this is because the rdf returned by
http://dbtune.org/data/<> doesn't include foaf:topicOf properties.
Kurt,
Yes, not describing the RDF data container (an information resource) is
a common oversight in the Semantic Web realm :-(
Note my comments to Pete re. the GeoSpecies Linked Data space on the
Bibliographic ontology mailing list [1]. He made the change, and bang!
/about/ did it's thing :-)
Links:
1.
http://groups.google.com/group/bibliographic-ontology-specification-group/browse_frm/thread/1c9a49ee71d4d9b4
Kingsley
cheers,
kurt j
On Wed, Feb 11, 2009 at 4:38 PM, Robert Jones <rjo...@openlinksw.com> wrote:
Kurt J wrote:
Ah I think I understand. So using /about/ is really not appropriate
for the sort-of on-demand generation of rdf that i'm doing. in that
http://dbtune.org/cmn/data/<composer> redirects to a sparql query for
describing <composer> and there wouldn't be a foaf:primaryTopic
property in that result. so to use /about/ i would want to generate
static rdf files (ie http://dbtune.org/cmn/data/WAGN.rdf) and host
them? is this what is done on dbpedia? is there a fancy programmatic
way of doing this from the rdf store?
Kurt,
I'm not entirely sure about what you are trying to achieve so I will run
down the typical check-list for getting /about/ to work on a simple RDF
view.
Assuming that you have installed a recent conductor vad, and rdf_mappers vad
you will automatically have an administration interface (conductor) that
will allow you create simple RDF views directly from DB tables in a few
clicks, and the /about/ virtual directory + required rewrite/redirect rules
courtesy of rdf_mappers.
If the /about/ virtual directory has not been altered then it will
automatically retrieve and display RDF data from remote or local stores,
hence we now need to ensure that local Virtuoso returns suitable RDF.
The simplest way to see how to create an RDF delivering endpoint is to allow
Virtuoso to do it for you from a database table. From the conductor go to
"Database" then "RDF Schema Object". Find a table that you would like from
RDF data from and click "Generate Single Mapping". You will be to a page
containing a SQL script to be run, note the following:
1. The necessary grants (as you have seen before)
2. The IRI class, which will contain the URI for accessing the data
3. The create graph statement which details the mapping from SQL table to
RDF.
4. The 4 create rewrite rules which instruct Virtuoso how to handle certain
clients/methods for accessing the to-be-created endpoint.
5. the virtual directory creation (vhost_define) using the rules from 4.
Once you hit the execute button and wait for confirmation that x number of
RDF manipulations were done you should be able to point your web browser to
a URL that resembles the URI from 2. above. This should automatically
redirect you to the /about/ service for viewing the RDF in an HTML format.
Please let me know how this compares with what you have already achieved and
are trying to achieve and we will see if we can overcome your current
hurdles.
Regards, Rob.
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