[oslc-core] olsc properties - "integer" value-type?

[Arthur Ryman]

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
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From:
James Conallen <jconallen at us.ibm.com>
To:
Scott Bosworth <bosworth at us.ibm.com>
Cc:
oslc-core at open-services.net, oslc-core-bounces at open-services.net
Date:
04/08/2010 12:51 PM
Subject:
Re: [oslc-core] olsc properties - "integer" value-type?
Sent by:
oslc-core-bounces at open-services.net



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
jconallen at us.ibm.com
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 at IBMUS

To:

oslc-core at open-services.net

Date:

04/08/2010 11:32 AM

Subject:

[oslc-core] olsc properties - "integer" value-type?

Sent by:

oslc-core-bounces at open-services.net



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 | bosworth at us.ibm.com | 
919.486.2197(w) | 919.244.3387(m) | 919.254.5271(f)
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