Re: looking for a social schema

Hi Steve,
Thank you a lot ! as usual you re incredibly effective :)

Take care
Ghalem

Le 18/11/2011 12:21, Steve Harris a écrit :
> Jena supports SPARQL 1.1, so you should be able to do a query something like:
>
> SELECT (COUNT(?friends) AS ?num_friends)
> WHERE {
>     <person>  foaf:knows ?friends
> }
>
> You can put this in a subquery if you need to use the number in other parts of the query.
>
> - Steve
>
> On 2011-11-18, at 10:53, Ghalem Ouadjed (EOWEO) wrote:
>
>> Thank you for your answers.
>>
>> i had to precise that i m wroking on a closed application and even if foaf doesn t contain the property i need the query works on Jena...
>>
>> to be less specific, i would like to know how to look for a schema based on a specific need regarding the property ? is there a way to determine that there is one or more schema which contain one or more property i envision to use. This could help to decide if i have to write a lightweight one or to use an existing one...
>>
>> I can realize that this kind of problematics doesn t correspond to a dogmatic vision but i know and experiment the needs of some middle size companies aiming to use semantic technologies in a pragmatic way for closed applications like internal KM solutions for instance and why not which could be enhanced and contextualised by linked datas...
>>
>> Thank you again for your time
>>
>> Cheers
>> Ghalem
>>
>> Le 18/11/2011 10:33, Heiko Paulheim a écrit :
>>> Due to the open world assumption, the value of that counter would (probably) we wrong.
>>>
>>> If I have
>>> :Peter foaf:knows :Stephen .
>>> :Peter foaf:knows :Marc .
>>>
>>> and, based on that knowledge, I added
>>>
>>> :Peter myschema:friendnb "2"^^xsd:integer .
>>>
>>> this would not be a valid conclusion - there may be a lot more friends of Peter which are not in my knowledge base (don't we all have friends without a facebook account?), and :Stephen and :Marc might even refer to the same person. In other words, with that approach, I would add knowledge to my knowledge base which is potentially wrong.
>>>
>>> So I would rather refrain from doing that.
>>>
>>> Best,
>>> Heiko.
>>>
>>> Am 18.11.2011 10:28, schrieb Melvin Carvalho:
>>>> On 18 November 2011 10:20, Heiko Paulheim<paulheim@ke.tu-darmstadt.de>   wrote:
>>>>> Dear Ghalem,
>>>>>
>>>>> since such a property would be in a conflict with the open world assumption
>>>>> underlying the semantic web (you simply cannot tell "how many things of type
>>>>> X are there" in an open world), I suppose there is no serious schema which
>>>>> has such a property.
>>>> What if you kept a separate tally to aggregate total friends as they are added?
>>>>
>>>>> Best,
>>>>> Heiko.
>>>>>
>>>>>
>>>>>
>>>>> Am 17.11.2011 18:40, schrieb Ghalem Ouadjed (EOWEO):
>>>>>
>>>>> Hi everyone,
>>>>> i would like to use a schema which is different and complementary of the
>>>>> foaf one, and which could contain a property like "number of friends".
>>>>>
>>>>> Does someone know an available ontology i could use pls?
>>>>>
>>>>> one of my query would look like :
>>>>>
>>>>> PREFIX rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>>>>> PREFIX rdfs="http://www.w3.org/2000/01/rdf-schema#"
>>>>> PREFIX dc="http://purl.org/dc/elements/1.1/"
>>>>> PREFIX foaf="http://xmlns.com/foaf/0.1/"
>>>>> PREFIX ............="_"
>>>>>
>>>>> SELECT ?friendnb   WHERE { ?Person   ...;;;;:friendnb   ?friendnb   }
>>>>> ------------
>>>>> | friendnb |
>>>>> ============
>>>>> | "\n330\n" |
>>>>> ------------
>>>>> Thank you in advance for your advices and your time
>>>>>
>>>>> Cheers
>>>>> Ghalem
>>>>>
>>>>> -- 
>>>>> Dr. Heiko Paulheim
>>>>> Knowledge Engineering Group
>>>>> Technische Universität Darmstadt
>>>>> Phone: +49 6151 16 6634
>>>>> Fax:   +49 6151 16 5482
>>>>> http://www.ke.tu-darmstadt.de/staff/heiko-paulheim
>>>
>>>

Received on Friday, 18 November 2011 12:14:08 UTC