[redland-dev] Does Rasqal support xsd:dataType?

[Seaborne, Andy]

-------- Original Message --------
> From: Hyunki Kim <mailto:hkk at etri.re.kr>
> Date: 25 April 2006 02:12
> 
> Dear members,
> 
> Many thanks to Andy and Christopher.
> 
> According to Andy's comments, I fixed the SPARQL query statement and
> the sample RDF document as follows: 
> 
> 1. SPARQL query
> 
> PREFIX dc:         <http://purl.org/dc/elements/1.1/>
> PREFIX xsd:    <http://www.w3.org/2001/XMLSchema#>
> SELECT ?d
> WHERE {
>     ?x  dc:date ?d .
>     FILTER ( datatype(?d) =
<http://www.w3.org/2001/XMLSchema#dateTime>
> ) } 

Minor tweak, making the best of a fundamental ugliness, you can write 

FILTER ( datatype(?d) = xsd:dateTime )

Note - no <> so it is a prefixed name.

	Andy

> 
> 2. RDF document
> 
> <?xml version="1.0"?>
> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>      xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
>      xmlns:dc="http://purl.org/dc/elements/1.1/">
>   <rdf:Description rdf:about="file:///purl.org/net/dajobe/">
>     <dc:title>Dave Beckett's Home Page</dc:title>
>     <dc:creator>Dave Beckett</dc:creator>
>     <dc:description>The generic home page of Dave
>     Beckett.</dc:description> <dc:date
>
rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2006-04-14T16:3
3:01
> </dc:date>
>   </rdf:Description>
> </rdf:RDF>
> 
> However, I found that the current version of Redland does not support
> the DATATYPE operator (http://librdf.org/rasqal/TODO.html). In
> addition, I had no results when I issued the query to Redland mysql
> storage.  
> Contary to the Redland mysql storage, when I queried to memory
storage,
> I had a result. 
> I would appreciate any kind of hints.
> Thanks.
> 
> Kim
> 
> 
> 
> -----Original Message-----
> From: Seaborne, Andy [mailto:andy.seaborne at hp.com]
> Sent: Monday, April 24, 2006 11:26 PM
> To: Christopher Schmidt; Hyunki Kim
> Cc: redland-dev at lists.librdf.org
> Subject: RE: [redland-dev] Does Rasqal support xsd:dataType?
> 
> 
> 
> 
> 
> -------- Original Message --------
> > From: Christopher Schmidt <>
> > Date: 24 April 2006 13:55
> > 
> > On Mon, Apr 24, 2006 at 05:14:55PM +0900, Hyunki Kim wrote:
> > > Hi,
> > > 
> > > After inserting a RDF document to the mysql, I had a problem in
> > > querying with the following SPARQL statement.
> > 
> > Use this instead:
> > 
> > 1. SPARQL Query
> > prefix dc:         <http://purl.org/dc/elements/1.1/>
> > PREFIX xsd:    <http://www.w3.org/2001/XMLSchema#>
> > SELECT ?d
> > WHERE { ?x  dc:date ?d^^<xsd:dateTime> . }#
> 
> The SPARQL idiom would be:
> 
> { ?x  dc:date ?d . FILTER ( datatype(?d) = <xsd:dateTime> ) }
> 
> but note that the <> is an absolute URI, and not a qname related to
the
> XSD 
> datatype dateTime.
> 
> The SPARQL grammar does not allow ?d^^<....>
> 
> In full:
> 
> prefix dc:         <http://purl.org/dc/elements/1.1/>
> PREFIX xsd:    <http://www.w3.org/2001/XMLSchema#>
> SELECT ?d
> WHERE {
>     ?x  dc:date ?d .
>     FILTER ( datatype(?d) = xsd:dateTime ) }
> 
> removing the <> on the prefixed name to get
> http://www.w3.org/2001/XMLSchema#dateTime
> 
> 	Andy
> 
> > 
> > 
> > or similar ... I'm not actually sure what the format for rdf
datatypes
> > is with NS prefixes: you can definitely use:
> > 
> > WHERE { ?x  dc:date ?d^^<http://www.w3.org/2001/XMLSchema#dateTime>
.
> > } 
> > 
> > If the above doesn't work.
> > 
> > --
> > Christopher Schmidt
> > Web Developer