Re: [Tracker] tracker-sparql dbus sparql results

[Jürgen Jakobitsch <j jakobitsch semantic-web at>]

hi philipp,

i'm currently using the dbus resource because i'm writing the openrdf repository in java and didn't want to got down the jni, jna road...

i already have built in a switch in tracker-resource.vala, about here [1], testing the cursor.get_value_type, but the returned value_types are not totally correct.

for some uris the value is 1 for other uris the value type is 2... i'm gonna issue a bug report, as soon as i have verified, that i'm not doing something wrong..
also the returned value_types are only 1 or 2.. there are not other values (like bnode, double, date...) although the returned string suggest they should be used..

wkr turnguard

[1] https://git.gnome.org/browse/tracker/tree/src/tracker-store/tracker-resources.vala#n102

| Jürgen Jakobitsch,
| Software Developer
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2014-04-18 11:32 GMT+02:00 Philip Van Hoof <philip codeminded be>:

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get_value_type and get_variable_name:

https://git.gnome.org/browse/tracker/tree/src/libtracker-sparql/tracker-cursor.vala#n126

https://git.gnome.org/browse/tracker/tree/src/libtracker-sparql/tracker-cursor.vala#n139

You btw shouldn't use the DBus Resources1 object, but use
libtracker-sparql instead.


Ivan Frade schreef op 17/04/2014 20:14:

> Hi Jürgen,
>
> Yes, tracker does not return bindingNames or types of the resulting
> nodes. It assumes the client takes care of interpreting the results
> of its query.
>
> A workaround would be to parse the SparQL in the wrapper and add
> that information when translating the DBus result set to the
> openrdf format. The binding Names can be added straight forward
> from the SELECT of the query. The type information is more
> complicated to deduce, based on the position in the query and/or
> the rdfs:range of the properties (defined in the ontology).
>
> Regards,
>
> Ivan
>
>
> On Thu, Apr 17, 2014 at 10:11 AM, Jürgen Jakobitsch <
> j jakobitsch semantic-web at> wrote:
>
>> hi,
>>
>> i'm currently developing an openrdf [1] repository implementation
>> with a tracker-sparql backend via dbus. this will enable java
>> developers to include tracker-sparql results in any application
>> (or create a sparql endpoint) extremly easily. openrdf's api is
>> quite common in the semweb community..
>>
>> everything is working very nice already  the only trouble i'm
>> having is that i get a vector of vectors containing simple
>> strings as a result object, meaning i need to find out types
>> (literals, uris, bnodes, typed literals)..
>>
>> is there any known way to retrieve some more information in the
>> results given via dbus? also bindingNames are missing...
>>
>> any pointer really appreciated wkr turnguard..
>>
>>
>> [1] http://www.openrdf.org/
>>
>> | Jürgen Jakobitsch, | Software Developer | Semantic Web Company
>> GmbH | Mariahilfer Straße 70 / Neubaugasse 1, Top 8 | A - 1070
>> Wien, Austria | Mob +43 676 62 12 710 | Fax +43.1.402 12 35 - 22
>>
>> COMPANY INFORMATION | web       : http://www.semantic-web.at/ |
>> foaf      :
>> http://company.semantic-web.at/person/juergen_jakobitsch PERSONAL
>> INFORMATION | web       : http://www.turnguard.com | foaf      :
>> http://www.turnguard.com/turnguard | g+        :
>> https://plus.google.com/111233759991616358206/posts | skype     :
>> jakobitsch-punkt | xmlns:tg  =
>> "http://www.turnguard.com/turnguard#"
>>
>> _______________________________________________ tracker-list
>> mailing list tracker-list gnome org
>> https://mail.gnome.org/mailman/listinfo/tracker-list
>>
>>
>
>
>
> _______________________________________________ tracker-list
> mailing list tracker-list gnome org
> https://mail.gnome.org/mailman/listinfo/tracker-list
>

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