- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Tue, 17 Dec 2002 11:11:20 -0500
- To: webont <www-webont-wg@w3.org>
I believe we reached consensus on how to close datatypes, but wanted to review the final decision. Here is what I believe is the current proposal (merging Peter and Jeremy's test) CLOSE DATATYPING AS FOLLOWS: 1/ The exchange syntax for OWL will use RDF datatyping. 2/ The abstract syntax for OWL will use <datatype><lexical> as the syntax for typed data values and will only allow lexical forms that are valid for the datatype, i.e., <xd:integer>1.5 is not a valid typed literal in the abstract syntax. 3/ OWL permits the use of the XML Schema built-in non-list simple types, using their canonical URI references. The following datatypes are RECOMMENDED for use with OWL: xsd:string, xsd:boolean, xsd:decimal, xsd:float, xsd:double, xsd:dateTime, xsd:time, xsd:date, xsd:gYearMonth, xsd:gYear, xsd:gMonthDay, xsd:gDay, xsd:gMonth, xsd:hexBinary, xsd:base64Binary, xsd:anyURI, xsd:normalizedString, xsd:token, xsd:language, xsd:NMTOKEN, xsd:Name, xsd:NCName, xsd:integer, xsd:nonPositiveInteger, xsd:negativeInteger, xsd:long, xsd:int, xsd:short, xsd:byte, xsd:nonNegativeInteger, xsd:unsignedLong, xsd:unsignedInt, xsd:unsignedShort, xsd:unsignedByte and xsd:positiveInteger. Other datatypes, including the other built-in XML Schema datatypes MAY be used. NOTE: specific considerations with the other built-in XML Schema datatypes are: xsd:duration, In this version of XML Schema no equality function is defined for xsd:duration. This may give surprising results when combined with OWL cardinality constraints. Later revisions of XML Schema datatypes are expected to provide such a function, in which case the revised duration datatype would be fully appropriate for use with OWL. xsd:QName, xsd:ENTITY, These datatypes require an enclosing XML document context, which may not be available in a specific application scenario for an OWL ontology. xsd:NOTATION, This datatype is intended for use as a base type for user defined datatypes. xsd:ID, xsd:IDREF, The use of xsd:NCName is RECOMMENDED in OWL. xsd:IDREFS, xsd:ENTITIES, xsd:NMTOKENS, List valued datatypes are OPTIONAL in OWL. 4/ Cardinality restrictions in the exchange syntax for OWL will use typed literals, as in _:x rdf:type owl:Restriction . _:x owl:onProperty ex:foo . _:x owl:cardinality "5"^^xsd:decimal . [note: I believe there was a wording change suggested here, but I cannot find it - can someone update this if I'm wrong] IN ADDITION, THE FOLLOWING WILL BE ADDED TO THE ISSUES LIST UNDER THE CLOSING TEXT FOR ISSUE 5.7 The Working Group believes that it is important to allow user-defined datatypes in OWL, and to refer to them by URI. A proposed solution is below, but it is possible that the XML-schema WG will propose a different mechanism, and thus we postpone this issue pending a recommendation from that group. Proposed use of URIs for user-defined types: OWL can use XML Schema non-list simple types defined at the top level of an XML Schema document and given a name, by using the URI reference constructed from the URI of the document and the local name of the simple type. That is, if U is the URI of an XML Schema document that contains, <xsd:schema ...> <xsd:simpleType name="foo"> <xsd:restriction base="integer"> <xsd:minInclusive value="1700"> </xsd:restriction> </xsd:simpleType> ... </xsd:schema> then the URI reference U#foo will be that datatype. Implementations of OWL may choose to ignore the facets such a type. -- Professor James Hendler hendler@cs.umd.edu Director, Semantic Web and Agent Technologies 301-405-2696 Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) Univ of Maryland, College Park, MD 20742 240-731-3822 (Cell) http://www.cs.umd.edu/users/hendler
Received on Tuesday, 17 December 2002 11:11:52 UTC