Re: New module proposal: tracker

[Philip Van Hoof <spam pvanhoof be>]

On Wed, 2009-08-19 at 11:25 +0100, Alan Cox wrote:

Hey Alan, thanks for your questions.

> > The tracker-store is a desktop service that offers the application
> > developer a query capability against data that it stores. The data that
> > it stores must be strictly defined by a schema (which is what in RDF is
> > called an ontology). The schemas that we ship by default are the Nepomuk
> > ones. The query language is SPARQL. The service provides the opportunity
> > to the application developer to store. The application developer uses
> > the an extension to SPARQL, SPARQL Update, which we support too. The
> > communication between application and tracker-store happens over DBus.
> > 
> > Nepomuk's ontologies:
> > http://www.semanticdesktop.org/ontologies/
> 
> Broken link btw at: http://www.semanticdesktop.org/ontologies/
> for:
> http://dev.nepomuk.semanticdesktop.org/repos/trunk/ontologies/pimo/latex/pimo.pdf

I will ping upstream Nepomuk maintainers about this problem. Thanks.

Note that Tracker at this moment doesn't do the PIMO ontology: we think
it's too complicated. This has not been finally decided yet, though.

> > Let me know if that was a helpful description for you. I tried hard not
> > to sound like an old German philosopher ;-).
> 
> One thing I couldn't quickly tell is whether you are always remembering
> the source of external information, particularly any externally acquired
> personal information about someone that is stored in the database.

To store the source of external information we need to do so called
named graphs (which is a RDF buzzword for namespaces).

Right now we don't do named graphs. We are in discussion about adding
support for it (actually, a few minutes ago we were), but given the
direction the discussion I don't think this feature will make it for the
first 0.7.x development releases.

More information about using named graphs with SPARQL queries can be
found here:

http://www.w3.org/TR/rdf-sparql-query/#namedGraphs

Our current implementation simply ignores any 'FROM NAMED' parts.

> That may be important for business users who have to meet data
> protection/personal information rights legislation. Ditto that tracker
> doesn't start extracting and organising by anything like religious,
> medical or ethnic data whose processing is controlled in many countries.

Tracker will store this if the applications request storage of it. The
issue of protecting the user's personal data is left to the applications
using it and the underlying operating system's security features.

The database's file will of course have the right UNIX permissions set.

-- 
Philip Van Hoof, freelance software developer
home: me at pvanhoof dot be 
gnome: pvanhoof at gnome dot org 
http://pvanhoof.be/blog
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