[redland-dev] combining models/inference support
Dave Beckett
dave.beckett at bristol.ac.uk
Wed Jul 27 12:33:19 BST 2005
On Tue, 2005-07-26 at 11:01 -0400, Vincent Carey 525-2265 wrote:
> I have just started creating an interface from R (www.r-project.org) to
> librdf.
>
> 1) I do not see a high-level function for combining RDF models, analogous
> to the Jena add method. Am I missing something, or must one write
> a combination function explicitly? If the latter, is it necessary
> to check for the existence of the statement to be added in the model
> to which it will be added?
There is no union model function or class, although there are
un-implemented methods predicting it's arrival sometime
(librdf_model_add_submodel - don't try it, it won't work)
One idea would be to add a new implementation of the librdf_model class,
which did union models. The code's already there, but the only
implementation right now is one that stores models in an librdf_storage
via the librdf_model_storage implementation. If a librdf_model_union
implementation class was made, you'd need to implement the librdf_model
methods.
Redland won't let you add duplicate statements (unless you are using
contexts).
> 2) Are there any mechanisms for computing entailments of RDF models
> in redland, or plans to introduce such mechanisms?
No immediate plans or time or energy for that from myself.
> I would be interested
> to know of C/C++ resources that can do this. For OWL inference it
> would seem that FaCT++ would be useful, but I am not clear on how
> FaCT++ resources can be used as a standalone library in conjunction
> with redland. Any experiences with this combination?
I had a look at FaCT++ but it was such a struggle to build it, I never
got to seeing how it could be used. It'd need a C API around it
probably. Mostly I don't know enough about this to give a convincing
answer.
Dave
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