Re: Datatype handling added to R2RML spec (ISSUE-29, ISSUE-48, ISSUE-51)

> Please review and comment!


Awesome job, looks good to me! And, yes, +1 to all three proposals ...

Cheers,
	Michael
--
Dr. Michael Hausenblas, Research Fellow
LiDRC - Linked Data Research Centre
DERI - Digital Enterprise Research Institute
NUIG - National University of Ireland, Galway
Ireland, Europe
Tel. +353 91 495730
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On 26 Aug 2011, at 00:56, Richard Cyganiak wrote:

> There's a new section in R2RML that discusses the handling of  
> datatypes:
> http://www.w3.org/2001/sw/rdb2rdf/r2rml/#datatype-conversions
>
> The definitions and tables in that section are referenced from  
> various places throughout the spec, in particular:
> http://www.w3.org/2001/sw/rdb2rdf/r2rml/#typed-literals
> http://www.w3.org/2001/sw/rdb2rdf/r2rml/#generated-rdf-term
>
> Some noteworthy features:
>
> - it is now an error to have a logical column that cannot be CAST to  
> string
> - unknown/user-defined types are CAST to string and mapped to plain  
> literal
> - rr:datatype is implicit if unspecified, that is, date column will  
> be xsd:date even without explicit rr:datatype
> - explicit rr:datatype that doesn't match the implicit type results  
> in typed literal where the lexical form is simply the result of CAST  
> to string
> - implementations MUST support literal well-formedness checks for  
> the 8 supported XSD types
> - implementations MAY support literal well-formedness checks for  
> additional types
> - ill-typed literal is a data error
> - I ignored INTERVAL because it's so freaking complicated
> - binary types get mapped to xsd:base64Binary
>
> Please review and comment!
>
>
> Process: I've set ISSUE-29, ISSUE-48 and ISSUE-51 to Pending Review  
> and propose:
>
> [[
> PROPOSAL: Close ISSUE-29; all places that interpret SQL values as  
> string now use "conversion to string"
> ]]
>
> [[
> PROPOSAL: Close ISSUE-48 as it is addressed in http://www.w3.org/2001/sw/rdb2rdf/r2rml/#datatype-conversions
> ]]
>
> [[
> PROPOSAL: Close ISSUE-51; the spec now demands that “supported RDF  
> types” MUST raise data error, and other types MAY raise data error
> ]]

Received on Friday, 26 August 2011 05:16:06 UTC