Re: rr:constant with literal or datatype

* tomasz.pluskiewicz@gmail.com <tomasz.pluskiewicz@gmail.com> [2014-11-16 14:31+0000]
> Thank you Richard
> 
> I have come to that conculsion after reading the specs carefully indeed.
> 
> Do you think such tests could be added to the suite? There a number of cases I can think of:
> 
> 1. Properly use the constant value as-is with dataype or language
> 2. Fail if a constant-valued has rr:datatype
> 3. Fail if a constant-valued has rr:language

Hi Tom, it sounds like you'd be the best one to write them. We can
either add them to the errata or figure out some sort of way to
communicate that there are other tests that weren't approved by the
WG. (In principle, I could just add them to the test suite, but that
seems to bypass an important social process.)


> Thanks,
> Tom
> 
> November 13 2014 7:10 PM, "Richard Cyganiak" <richard@cyganiak.de> wrote: 
> > Tomasz,
> > 
> >> On 7 Nov 2014, at 17:57, tomasz.pluskiewicz@gmail.com wrote:
> >> 
> >> Hi
> >> 
> >> I haven't found such example and I'm not sure what should happen if the R2RML mapping contained a
> >> constant with language tag or datatype. For example
> >> 
> >> [ rr:constant "someObject"^^<http://example.org/some#datatype> ]
> > 
> > There’s indeed no test case for this. So you’ll have to check the text of the spec.
> > 
> >> Should the datatype be ignored or used as if it was specified using rr:datatype?
> > 
> > As per R2RML §11.2:
> > 
> > [[
> > The generated RDF term of a term map for a given logical table row is determined as follows:
> > • If the term map is a constant-valued term map, then the generated RDF term is the term map's
> > constant value.
> > ]]
> > http://www.w3.org/TR/r2rml/#generated-rdf-term
> > 
> > And:
> > 
> > [[
> > The constant value of a constant-valued term map is the RDF term that is the value of its
> > rr:constant property.
> > ]]
> > http://www.w3.org/TR/r2rml/#dfn-constant-value
> > 
> > So, yes, the value of rr:constant is used exactly as is, including datatype if present.
> > 
> >> And more interestingly what should happen for the mapping below? Answering the first question
> > will
> >> suggest the answer.
> >> 
> >> [
> >> rr:constant "someObject"^^<http://example.org/some#datatype> ;
> >> rr:datatype <http://example.org/some#datatype>
> >> ]
> > 
> > [[
> > A term map that is not a datatypeable term map MUST NOT have an rr:datatype property.
> > ]]
> > http://www.w3.org/TR/r2rml/#dfn-specified-datatype
> > 
> > Following the definitions, you will find that constant-valued term maps (those with rr:constant) do
> > not have a term type, and therefore can’t have a term type of rr:Literal, and therefore are not
> > datatypeable.
> > 
> > Best,
> > Richard
> > 
> >> It looks like such cases aren't included in the test suite [1].
> >> 
> >> Kind regards,
> >> Tom
> >> 
> >> [1] http://www.w3.org/2001/sw/rdb2rdf/test-cases
> 

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Received on Sunday, 16 November 2014 18:45:31 UTC