- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Tue, 2 Aug 2011 21:09:24 +0100
- To: Nuno Lopes <nuno.lopes@deri.org>
- Cc: W3C RDB2RDF <public-rdb2rdf-wg@w3.org>
On 2 Aug 2011, at 17:39, Nuno Lopes wrote: >> Is xsd:date for TIME a typo? > > Yes, fixed. Ok, cheers. >> How exactly should I read the “or”/“and” in the XSD column? > > The spec further defines an algorithm for this mapping, for instance, the "or" for FLOAT is dependent on the precision of the datatype in the implementation: under 24 bits is an xs:float otherwise is an xs:double. Not sure if all cases are this simple, I will check. Ok. Would be great if this were documented in the wiki page as well. Note that RDF doesn't allow the expression of facets on XSD datatypes, so I think we can more or less ignore that part. >> For things like boolean and dates and times and durations, how exactly is the syntactic correspondence for the values? I mean, a normal SQL datetime literal isn't in the right lexical form for an XSD datetime literal. (I think there's a section in Part 14 about that, something about "data values"?) > > Regarding the lexical form of dates, times, and durations the facet is used to restrict the lexical value of the XSD datatype and the algorithm (which I did not look into in detail yet) seems to define a regular expression for the conversion from the SQL datatype to a valid form of the XSD datatype. What we'll have to explain in the spec is basically: Given an input SQL data value v of SQL datatype ST, what transformation do we have to do on the value in order to derive a lexical form l of XSD datatype XT? We can omit discussing the transformation for any type where the default CAST to string behaviour doesn't produce the right result. Best, Richard >>> [1] http://www.w3.org/2001/sw/rdb2rdf/wiki/Mapping_SQL_datatypes_to_XML_Schema_datatypes
Received on Tuesday, 2 August 2011 20:10:04 UTC