[rights-specification] Re: [rights] CR on ISO Codes

[Bob Glushko <glushko@SIMS.Berkeley.EDU>]

> You should take a look
> at the UBL position paper on code lists, which very thoroughly
> analyzes  6 different models for encoding code
> lists.


The methods for handling code lists in schemas are as
follows:

·       The enumerated list method, using the classic method of statically enumerating the valid codes corresponding to a code list in an XSD string-based type internally in UBL

·       

The
QName in content method, involving the use of XML Namespaces-based
“qualified names” in the content of elements, where the namespace
URI is associated with the supplementary components

·       

The
instance extension method, where a code is provided along with a
cross-reference to somewhere in the same instance to the necessary
supplementary information

·       

The
single type method, involving a single XSD type that sets up
attributes for supplying the supplementary components directly on all
elements containing codes

·       

The
multiple UBL types method, where each element dedicated to
containing a code from a particular code list is bound to a unique UBL
type, which external organizations must derive from

·       

The
multiple namespaced types method, where each element dedicated to
containing a code from a particular code list is bound to a unique type
that is qualified with a (potentially external) namespace



http://www.oasis-open.org/committees/ubl/ndrsc/pos/p-maler-codelists-09.doc

here is a schema template for the recommended approach, (the last one in
the list above) which shows a very general way to handle code lists 
-- it has the semantic clarity of the classic approach of enumerated
values but is much better from the perspective of reusing externally
defined schemas.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema
  targetNamespace="{namespace for ISO 3166 code list
module}"
  xmlns=”http://www.w3.org/2001/XMLSchema”
  xmlns:iso3166="{namespace for ISO 3166 code list
module}"
  xmlns:xs=”http://www.w3.org/2001/XMLSchema”
  elementFormDefault="unqualified"
  attributeFormDefault="unqualified">
  <xs:simpleType name=”iso3166:CodeContentType”>
    <xs:extension base=”xs:token”>
      <xs:enumeration value=”DE”/>
      <xs:enumeration value=”FR”/>
      <xs:enumeration value=”US”/>
      . . .
    </xs:extension>
  </xs:simpleType>

  <xs:complexType name=”iso3166:CodeType”>
    <simpleContent>
      <xs:extension
base="iso3166:CodeContentType">
        <xs:attribute
name="ID"
         
type="xs:token" fixed=”ISO 3166 Locale Code”/>
        <xs:attribute
name="agencyID"
         
type="xs:token" fixed=”ISO”/>
        <xs:attribute
name="versionID"
         
type="string" fixed=”1.0”/>
    </simpleContent>
  </xs:complexType>
</xs:schema>

--
Robert J. Glushko, Ph.D.
School of Information Management & Systems
102 South Hall
University of California, Berkeley CA 94720-4600