This is the archive of the goodrelations dicussion list

Dear all:

As the amount of GoodRelations data is growing, I wanted to stress that 
you can use the Virtuoso dataspace at

http://loc.openlinksw.com/sparql

for queries. We are currently trying to get all available GoodRelations 
data into that space and keep it up-to-data.

That means that application developers

- don't have to crawl the whole Web for relevant RDF
- can use the powerful parallelization techniques and SPARQL extensions 
from Virtuoso.


If you want to give it a try: Simply paste the following query: It lists 
the first 50 items in the space that cost between 5 and 10 EUR or 7 and 
14 USD.

PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX gr:<http://purl.org/goodrelations/v1#>

SELECT ?s ?p ?c
WHERE {
?s a gr:Offering.
?s gr:hasPriceSpecification ?ps.
?ps gr:hasCurrencyValue ?p.
?ps gr:hasCurrency ?c.
FILTER ((regex(?c, "EUR") && ?p >"5"^^xsd:float && ?p <"10"^^xsd:float) 
|| (regex(?c, "USD") && ?p >"7"^^xsd:float && ?p <"14"^^xsd:float))

} LIMIT 50


Also, you can use the next query to watch the growth in instance data. 
It lists all GoodRelations classes and determines the amount of instances.

# List of Class Frequency

SELECT ?class, count(?instance) as ?freq WHERE
   {
    ?instance a ?class.
    {SELECT ?class FROM <http://purl.org/goodrelations/v1#> WHERE
     {?class a owl:Class. }
    }
   }

Since Virtuoso is a quad store, you can constrain the expressions to 
individual graphs or graph groups. This is how the previous query 
constraints the list of classes to those defined in GoodRelations.

Also, note that Virtuoso supports nesting and subqueries.

Best wishes

Martin



-- 
--------------------------------------------------------------
martin hepp
e-business & web science research group
universitaet der bundeswehr muenchen

e-mail:  mhepp at computer.org
phone:   +49-(0)89-6004-4217
fax:     +49-(0)89-6004-4620
www:     http://www.unibw.de/ebusiness/ (group)
         http://www.heppnetz.de/ (personal)
skype:   mfhepp 
twitter: mfhepp

Check out GoodRelations for E-Commerce on the Web of Linked Data!
=================================================================

Webcast:
http://www.heppnetz.de/projects/goodrelations/webcast/

Recipe for Yahoo SearcMonkey:
http://tr.im/rAbN

Talk at the Semantic Technology Conference 2009: 
"Semantic Web-based E-Commerce: The GoodRelations Ontology"
http://tinyurl.com/semtech-hepp

Overview article on Semantic Universe:
http://tinyurl.com/goodrelations-universe

Project page:
http://purl.org/goodrelations/

Resources for developers:
http://www.ebusiness-unibw.org/wiki/GoodRelations

Tutorial materials:
CEC'09 2009 Tutorial: The Web of Data for E-Commerce: A Hands-on Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey
http://tr.im/grcec09

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