James, I agree in principle, however there are a lot of XSD datatypes and they are sometimes merely variants of each other, e.g. is the value "42"^^xsd:int really the same concept as "42"^^xsd:integer or "42"^^xsd:positiveInteger? They all map to the same element of the numeric value space. How does this affect comparisons in queries? I think we'd have to write queries that pulled out the untyped part to do comparisons, e.g. in SPARQL using the STR function.
1. RDF distinguishes plain literals from typed literals. Plain literal are simple character strings, whereas typed literals have the ^^<datatype> suffix. Technically, we should then use the rdf:datatype attribute in all property elements that have typed literal values. We haven't given any OSLC guidance on when to use typed literals versus plain literals. If we use typed literals and all the XSD datatypes, this makes writing queries more complex since we have to get the datatypes right too. 2. Not all XSD datatypes are suitable for use in RDF, e.g. xsd:QName. The set of suitable datatypes is given in [1] 3. For URI literals, we should use xsd:anyURI unless there is a subtle distinction, not invent the new URI http://open-service.net/xmlns/oslc-core/literal-types#URI 4. For XML literals we should use rdf:XMLLiteral, not invent a new URI http://open-service.net/xmlns/oslc-core/literal-types#XMLLiteral [1] http://www.w3.org/TR/rdf-mt/#DTYPEINTERP Regards, ___________________________________________________________________________ Arthur Ryman, PhD, DE Chief Architect, Project and Portfolio Management IBM Software, Rational Markham, ON, Canada | Office: 905-413-3077, Cell: 416-939-5063 Twitter | Facebook | YouTube From: James Conallen <[email protected]> To: Scott Bosworth <[email protected]> Cc: [email protected], [email protected] Date: 04/08/2010 12:51 PM Subject: Re: [oslc-core] olsc properties - "integer" value-type? Sent by: [email protected] I always feel uneasy about limiting something like data types in a context where we are defining a common specification for domains and use cases that we haven't even defined yet. Rather, I'd like to say that we can support any XML Schema defined data type in a RDF document. For example in queries this would mean that we can optionally qualify values with the type ( i.e. oslc.where=dc:created>"2010-04-07T19:57:05.375Z"^^xsd:dateTime ). BTW: I see the following in the current draft of the core: oslc:valueType (URI, exactly-one) - may be any of the value types listed above in OSLC Defined Resources, in URI form: Literal value-types String - http://www.w3.org/2001/XMLSchema#string Integer - http://www.w3.org/2001/XMLSchema#int Decimal - http://www.w3.org/2001/XMLSchema#decimal Float - http://www.w3.org/2001/XMLSchema#float Double - http://www.w3.org/2001/XMLSchema#double Boolean - http://www.w3.org/2001/XMLSchema#boolean DateTime - http://www.w3.org/2001/XMLSchema#dateTime URI - http://open-service.net/xmlns/oslc-core/literal-types#URI XMLLiteral - http://open-service.net/xmlns/oslc-core/literal-types#XMLLiteral Resource value-types Resource - http://open-service.net/xmlns/oslc-core/resource-types#Resource In-Line - http://open-service.net/xmlns/oslc-core/resource-types#InLine Complex - http://open-service.net/xmlns/oslc-core/resource-types#Complex <jim/> jim conallen [email protected] Rational Software, IBM Software Group Scott Bosworth---04/08/2010 11:32:40 AM---Dave, did we conclude yesterday that "integer" should be included in the list of literal value-types From: Scott Bosworth/Raleigh/IBM@IBMUS To: [email protected] Date: 04/08/2010 11:32 AM Subject: [oslc-core] olsc properties - "integer" value-type? Sent by: [email protected] Dave, did we conclude yesterday that "integer" should be included in the list of literal value-types in defining oslc properties? and in the resource shape section as well? Should I log an issue for this? Thanks....Scott Scott Bosworth | IBM Rational CTO Team | [email protected] | 919.486.2197(w) | 919.244.3387(m) | 919.254.5271(f) _______________________________________________ Oslc-Core mailing list [email protected] http://open-services.net/mailman/listinfo/oslc-core_open-services.net _______________________________________________ Oslc-Core mailing list [email protected] http://open-services.net/mailman/listinfo/oslc-core_open-services.net
