- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Thu, 13 Nov 2014 18:09:59 +0000
- To: tomasz.pluskiewicz@gmail.com
- Cc: public-rdb2rdf-comments@w3.org
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 >
Received on Thursday, 13 November 2014 18:10:24 UTC