[Tracker] Tracker and Semantic links

[scaroo <scaroo gmail com>]

Hi jamie and kudos for your greqt work.
I am a satisfied user of Tracker particularly with the Deskbar Handler !
I d like to know if you plane to allow the user (or dev) to be able to
define links between first class object type. Well that s not clear,
shame on my poor English, so here is an example :
we have a picture and a people, they can be linked by many different
ways : "is_authored_by",  "represents", "adviced_by", "taken_by",
"gimped_by" and so on...

Instead of creating tags representing those links, why not describe
them formally and then using them as a bridge between two or more
objects ? The user could define new kind of links. For example, a
photographer could define a "buyed_by" link and so could find any
customer having bought a particular picture. More interestingly, the
links being bi-directional, he could find all the pictures bought by
one client.
And you know what ? A XML dialect exists just for that : OWL
For example, to define the link "is_located_in", linking a city and a
country can be described like this :

<!-- définition of classes "city" et "Country" -->
<owl:Class rdf:ID="City" />
<owl:Class rdf:ID="Country" />

<!-- définition of the propertie « is_located_in » -->
<owl:ObjectProperty rdf:ID="isLocatedIn">
<rdfs:domain rdf:resource="#City" />
<rdfs:range rdf:resource="#Country" />
</owl:ObjectProperty>

<!-- création of "France" -->
<Country rdf:ID="France">
<name>France</name>
</Country>

<!-- création of "Paris", located in France -->
<City rdf:ID="Paris">
<name>Paris</name>
<isLocatedIn rdf:resource="#France" />
</City>


Another remark, on the freedesktop project page, it is stated that you
will support Contact as a first class object type. Why not extends
this concept to People, of who i can optionally have some contact
informations ?
For example, if I want to query tracker for the sound compositor of a
movie I have on my disk, I d like to know which other movies I own he
worked on, his age, etc... Of course, that suppose that tracker has
this information, maybe from the ogg/thera tags or something, but the
point is that I do not know this people, I do not have any contact
data about him/her, but I d like to know more about him.

Maybe all of this is out of the scope of Tracker, but that would be a
big step to the buzzworded Semantic Desktop.
Thanks for your time !