Re: [xml-dev] Is there a way to reuse and extend an enumeration in XML schema

["William J. Kammerer" <wkammerer@novannet.com>]

But if Kenneth Stephen's requirement (" without altering the original
[schema] definition") is anything like UBL's (John Bosak said "the code
list [is to] be extended without modifying the UBL schemas." ), then you
don't have the freedom "to change element declarations accordingly -
i.e. elements that are currently declared as being of your original
simple type would have to be of your new simple type."  The UBL
documents are described by a huge rat's nest of schemas and it is not
at all practical for the UBL user to be making changes in multiple
places within those schemas (unless he had a powerful modeling and
schema editing tool like Gefeg's EDIFIX).

I'd also take as a strongly implied requirement that element and
attribute names used in the *instance* data should not change either.
In the UBL situation, as soon as the underlying code list has been
updated by the maintenance authority, you'd want to easily remove the
"override" and "revert" to the (new) standard off-the-shelf UBL schemas.
The only freedom you have is to refer to a new schema in the instance
data (whose only purpose is to cause the "override" of the enumeration
to include new allowable code values).

William J. Kammerer
Novannet
Columbus, OH 43221-3859 . USA
+1 (614) 487-0320

----- Original Message ----- 
From: "Chiusano Joseph" <chiusano_joseph@bah.com>
To: "Kenneth Stephen" <marvin.the.paranoid@gmail.com>; "XML Developers
List" <xml-dev@lists.xml.org>
Sent: Saturday, 05 March, 2005 11:01 PM
Subject: RE: [xml-dev] Is there a way to reuse and extend an enumeration
in XML schema


Try using the W3C Schema "union" datatype for this (if that's not the
correct approach, Jeni Tennison, Henry Thompson or others will be along
shortly to correct me, I'm sure).

So you would define an additional simple type as follows (note that
"your_current_simple_type_name" refers to the simpleType you referred to
when you said "I have a simpleType defined as..."):

<simpleType name="new_simple_type_name">
  <union memberTypes="your_current_simple_type_name">
    <simpleType>
      <restriction base="NMTOKEN">
        <enumeration value="D"/>
      </restriction>
    </simpleType>
  </union>
</simpleType>

You would then need to change element declarations accordingly - i.e.
elements that are currently declared as being of your original simple
type would have to be of your new simple type.

Kind Regards,
Joseph Chiusano
Booz Allen Hamilton
Strategy and Technology Consultants to the World

----- Original Message ----- 
From: "Kenneth Stephen" <marvin.the.paranoid@gmail.com>
To: "XML Developers List" <xml-dev@lists.xml.org>
Sent: Saturday, 05 March, 2005 06:28 PM
Subject: [xml-dev] Is there a way to reuse and extend an enumeration in
XML schema


Hi,

    I have a simpleType defined as having an enumerated type having
(for example) values 'A','B', and 'C'. I want to be able to reuse this
type elsewhere and also add an additional value of 'D' without
altering the original definition. Is there a way to do that?

Thanks,
Kenneth