This seems to do what Farid wanted, and it validates in xmlspy 2005 sp2:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" =
elementFormDefault="qualified" attributeFormDefault="unqualified">
	<xs:element name="measurements">
		<xs:annotation>
			<xs:documentation>Testing my understanding of xs:key and xs:keyref.  =
If this works, it could become the basis for translating an FDDL into an =
XML schema.</xs:documentation>
		</xs:annotation>
		<xs:complexType>
			<xs:sequence>
				<xs:element name="validTypes">
					<xs:complexType>
						<xs:sequence>
							<xs:element name="validType" type="xs:string" =
maxOccurs="unbounded"/>
						</xs:sequence>
					</xs:complexType>
				</xs:element>
				<xs:element name="measurement" maxOccurs="unbounded">
					<xs:complexType>
						<xs:sequence>
							<xs:element name="name" type="xs:string"/>
							<xs:element name="type" type="xs:string"/>
						</xs:sequence>
					</xs:complexType>
				</xs:element>
			</xs:sequence>
		</xs:complexType>
		<xs:key name="validType">
			<xs:selector xpath="validTypes/validType"/>
			<xs:field xpath="."/>
		</xs:key>
		<xs:keyref name="measurementType" refer="validType">
			<xs:selector xpath="measurement"/>
			<xs:field xpath="type"/>
		</xs:keyref>
	</xs:element>
</xs:schema>

<?xml version="1.0" encoding="UTF-8"?>
<!-- edited with XMLSpy v2005 sp2 U (http://www.altova.com) by Rene =
Brunner (UBS AG) -->
<measurements xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" =
xsi:noNamespaceSchemaLocation="D:\My =
Documents\Work\WBml\Forms\Schema\keyrefTest.xsd">
	<validTypes>
		<validType>analog</validType>
		<validType>digital</validType>
		<validType>bus</validType>
		<validType>undefined</validType>
	</validTypes>
	<measurement>
		<name>airflow</name>
		<type>analog</type>
	</measurement>
	<measurement>
		<name>heading</name>
		<type>digital</type>
	</measurement>
</measurements>

Regards,
Richard

> -----Original Message-----
> From: xmlschema-dev-request@w...
> [mailto:xmlschema-dev-request@w...]On Behalf Of Kasimier Buchcik
> Sent: Thursday, February 17, 2005 20:40
> To: Farid.Mahini@L...
> Cc: xmlschema-dev@w...
> Subject: Re: Facets
> 
> 
> 
> Hi,
> 
> Farid.Mahini@L... wrote:
> > Thank you for your comment.
> > 
> > I am planning on using this method (actually currently in 
> the middle of
> > Michael Kay's XSLT2.0 book) in the way you mentioned it:
> > 
> > I am creating XML files for running tests on various 
> 'boxes' which have
> > different configurations (#of cards, channels, so on). I 
> was planning on
> > using the XSLT to create the hardware dependant schema 
> using user hardware
> > selection.  It seems I am on the righttrack on that section 
> of the task. 
> > 
> > However, within each XML document, the user defines their own set of
> > definitions to be used as enum values.  Michael Kay 
> suggested using the
> > 'key/keyref' elements; I tried it, but XMLSpy  seems to 
> validate it even
> > though I intentionally used an invalid attribute. I am new 
> at this and could
> > be my code.  Please point my error in the following example 
> I used to test
> > the key/keyref element? 
> > 
> > The schema:
> > <xs:schema  ....>
> > 	<xs:element name="Measurements">
> > 		<xs:complexType>
> > 			<xs:sequence>
> > 				<xs:element name="AAA" type="myAAA"/>
> > 				<xs:element name="BBB" type="myBBB"/>
> > 			</xs:sequence>
> > 		</xs:complexType>
> > 		<xs:key name="myId">
> > 			<xs:selector xpath="./AAA/a"/>
> > 			<xs:field xpath="@a"/>
> > 		</xs:key>
> > 		<xs:keyref name="myIdref" refer="myId">
> > 			<xs:selector xpath="./BBB/b"/>
> > 			<xs:field xpath="@b"/>
> > 		</xs:keyref>
> > 	</xs:element>
> > 	<xs:complexType name="myAAA">
> > 		<xs:sequence>
> > 			<xs:element name="a" maxOccurs="unbounded">
> > 				<xs:complexType>
> > 					<xs:attribute name="id"
> > type="xs:string" use="required"/>
> > 				</xs:complexType>
> > 			</xs:element>
> > 		</xs:sequence>
> > 	</xs:complexType>
> > 	<xs:complexType name="myBBB">
> > 		<xs:sequence>
> > 			<xs:element name="b" maxOccurs="unbounded">
> > 				<xs:complexType>
> > 					<xs:attribute name="idref"
> > type="xs:string" use="required"/>
> > 				</xs:complexType>
> > 			</xs:element>
> > 		</xs:sequence>
> > 	</xs:complexType>
> > </xs:schema>
> > 
> > 
> > The XML input doucment:
> > <Measurements .....>
> >   <AAA> 
> >     <a id="x"/> 
> >     <a id="y"/> 
> >   </AAA> 
> >   <BBB> 
> >     <b idref="x"/> 
> >     <b idref="y"/> 
> >     <b idref="z"/>    // should cause an error since only 
> 'x' and 'y' are
> > valid choices.
> >   </BBB>
> > 
> > </Measurements>
> [...]
> 
> XMLSpy does not evaluate this correctly. The XPath expression 
> of the IDC
> fields used here should resolve to the attributes "a" or "b" only.
> If those XPath expressions are substituted for "@id" and 
> "@idref" I get
> keyref error you expected with Libxml2, Xerces 2.6.2 and XSV 2.7.
> 
> Regards,
> 
> Kasimier
> 
> 

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