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RE: Original Choice (was RE: Choice)

From: Dare Obasanjo <dareo@microsoft.com>
Date: Tue, 12 Mar 2002 16:47:01 -0800
Message-ID: <8BD7226E07DDFF49AF5EF4030ACE0B7E05573BB4@red-msg-06.redmond.corp.microsoft.com>
To: "Beyer,Nathan" <NBEYER@cerner.com>, "Naren Chawla" <naren_chawla@attbi.com>, "Schema Dev XML (E-mail)" <xmlschema-dev@w3.org>
> -----Original Message-----
> From: Beyer,Nathan [mailto:NBEYER@cerner.com] 
> Sent: Tuesday, March 12, 2002 3:59 PM
> To: Dare Obasanjo; Naren Chawla; Schema Dev XML (E-mail)
> Subject: RE: Original Choice (was RE: Choice)
> Well, if I'm reading the normative XML Schema correctly 
> (http://www.w3.org/2001/XMLSchema.xsd), then I'm even more confused.
> According to the that schema, the element "choice" is of type 
> "xs:explicitGroup." "xs:explicitGroup" is an extension of 
> "xs:group," which allows the minOccurs and maxOccurs attributes.
> But, according to the schema, the element "group" is of type 
> "xs:namedGroup." "xs:namedGroup" has a choice between "all," 
> "choice," and "sequence." The "choice" in here is is of type 
> "xs:simpleExplicitGroup" which prohibits the user of the 
> minOccurs and maxOccurs attributes.
> Am I reading that correctly?

The third to sixth lines of the document you quote from are

	<!--  Note this schema is NOT the normative structures schema.
	<!--  The prose copy in the structures REC is the normative
      <!--  version (which shouldn't differ from this one except for -->

      <!--  this comment and entity expansions, but just in case     -->

Experience has thought me to ignore non-normative references as credible
sources of information especially with regards to the XML Schema
recommendation. However, I have not investigated this specific incidence
and will defer specific comments until later. 
> To me the ambigous piece of using a choice how to interpret 
> the occurs attributes on the choice compositor in conjunction 
> with the occurs attributes on the particles within the 
> choice, especially when they are in conflict.
> For example, how do I interpret this:
> 			<xs:choice minOccurs="1" maxOccurs="1">
> 				<xs:element name="choice1" minOccurs="0"
> maxOccurs="1"/>
> 				<xs:element name="choice2" minOccurs="0"
> maxOccurs="1"/>
> 			</xs:choice>
> -or this one:
> 			<xs:choice minOccurs="0" maxOccurs="unbounded">
> 				<xs:element name="choice1" minOccurs="1"
> maxOccurs="1"/>
> 				<xs:element name="choice2" minOccurs="1"
> maxOccurs="1"/>
> 			</xs:choice>

The rules for determining this are specified in the XML Schema
Structures recommendation in the section entitled "Schema Component
Constraint: Effective Total Range (choice)" at


The artifact which is the source of my power will not be kept on the
of Despair beyond the River of Fire guarded by the Dragons of Eternity.
will be in my safe-deposit box. The same applies to the object which is
one weakness.
Received on Tuesday, 12 March 2002 19:47:27 UTC

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