- From: OWL Working Group Issue Tracker <sysbot+tracker@w3.org>
- Date: Sun, 20 Jan 2008 12:55:23 +0000 (GMT)
- To: public-owl-wg@w3.org
ISSUE-95 (Datatype-facet compatibility in DatatypeRestriction): No compatibility restrictions between the datatype being restricted and the facets in the DatatypeRestriction construct http://www.w3.org/2007/OWL/tracker/issues/ Raised by: Boris Motik On product: Hello, I believe that we have a slight problem with the DatatypeRestriction. 1. Problem ---------- Currently, the DatatypeRestriction construct takes one dataRange and several facet-value pairs. Note two important points here: - The data range can be complex. - There are no compatibility restrictions between the data range and the facets. The first point makes it possible to write DatatypeRestriction( DataComplementOf(xsd:nonnegativeInteger) fractionDigits "2"^^xsd:integer). It is unclear how to interpret this datatype. The complement of xsd:nonnegativeInteger contains all data values that are not nonnegative integers, which includes, say, real numbers, but also includes all strings. It is unclear what restricting such a datatype to 2 precision digits means. Originally, a dataRange was used because this allowed one to specify, say, minInclusice and maxIncludive via nesting; with mutliple facets per DatatypeRestriction this is not necessary any more. The second point makes it possible to write DatatypeRestriction(xsd:string fractionDigits "2"^^xsd:integer). Again, it is unclear whether this is a syntax error or, if not, how to interpret this datatype. 2. Possible solution -------------------- A possible solution would be to change the definition of DatatypeRestriction in the following way: - Rather than taking a dataRange as an argument, we should make DatatypeRestriction take a Datatype as an argument. - We should specify compatibility between different datatypes and factes. For example, we would say that fractionDigits could be applied only to the xsd:float datatype. This solution seems to be in line with the XML Schema way of handling things: if I am not mistaken, in XML Schema one cannot apply an arbitrary facet to an arbitrary datatype. Regards, Boris
Received on Sunday, 20 January 2008 12:55:30 UTC