XMI24 — MOF/XMI schemaType is incorrectly defined relative to its use and its scope is too restrictive

MOF/XMI defines the schemaType tag as follows: "The name of a datatype defined in the XML Schema Datatype specification."

First,the examples in the MOF/XMI specification and current use of this tag in OMG's XMI artifacts use datatype URIs, not datatype names.

Second, the definition of this tag is vague about which datatypes are allowed.

• The builtin datatypes explicitly defined in the XML Schema Datatype spec? http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/#built-in-datatypes
• Any datatype defined in the "xs" namespace?

Consider for example "precision decimal", a datatype that is explicitly mentioned but not explicitly defined in the XML Schema Datatypes spec: http://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/#primitive-vs-derived
This datatype is explicitly defined in a different specification but in the "xs" namespace: http://www.w3.org/TR/xsd-precisionDecimal/#precisionDecimal

This example illustrates the ambiguity of the scope as currently specified, that is, is "xs:precisionDecimal" allowed as a value for schemaType?

Third, even if schemaType were to be clarified to be some subset of datatypes defined in the "xs" namespace, there are legitimate business reasons to expect greater flexibility.

- Several OMG specifications define XSDs (e.g., BPMN, DTV, …) If these include XML Schema datatype definitions, why are we precluded from referring to them via a PrimitiveType that has a schemaType tag pointing to their URI?

• For working with RDF, it would make sense to define a PrimitiveType whose schemaType tag maps it to rdf:PlainLiteral — I.e., http://www.w3.org/TR/rdf-plain-literal/#Definition_of_the_rdf:PlainLiteral_Datatype
• Similarly, for OWL, it would make sense to define PrimitiveType that would be mapped to owl:Rational and owl:Real: http://www.w3.org/TR/2012/REC-owl2-syntax-20121211/#Datatype_Maps