Hi All!
I run into a problem defining a XSD schema with KEYREF references.
Is it possible to use KEYREF with nillable fields?
Just like a database where a FK could be null.
In the example below the tag <Owner> is nillable
and also used as FIELD in the KEYREF.
Run this in Visual Studio 2005 XML Editor and there will be NO error.
Run this in XMLSpy and there WILL BE an error.
Anyone out there with any suggestions or workarounds?
Regards
/Stefan Vestin
<== FILENAME=KeyRef.xml ==>
<?xml version="1.0" encoding="UTF-8"?>
<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="testNS KeyRef.xsd" xmlns="testNS">
<Persons>
<Person ID="123">
<Name>John</Name>
</Person>
<Person ID="456">
<Name>Frank</Name>
</Person>
</Persons>
<Vehicles>
<Vehicle ID="ABC">
<Owner xsi:nil="true"></Owner> <=== Reference that is NULL
</Vehicle>
</Vehicles>
</root>
<== FILENAME=KeyRef.xsd ==>
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:t="testNS"
targetNamespace="testNS" elementFormDefault="qualified"
attributeFormDefault="unqualified">
<xs:element name="root">
<xs:complexType>
<xs:sequence>
<xs:element name="Persons">
<xs:complexType>
<xs:sequence maxOccurs="unbounded">
<xs:element name="Person">
<xs:complexType>
<xs:sequence>
<xs:element name="Name" type="xs:string"/>
</xs:sequence>
<xs:attribute name="ID" type="xs:string"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="Vehicles">
<xs:complexType>
<xs:sequence maxOccurs="unbounded">
<xs:element name="Vehicle">
<xs:complexType>
<xs:sequence>
<xs:element name="Owner" type="xs:string"
nillable="true"/>
</xs:sequence>
<xs:attribute name="ID" type="xs:string"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
<xs:key name="PersonKey">
<xs:selector xpath=".//t:Person"/>
<xs:field xpath="@ID"/>
</xs:key>
<xs:keyref name="OwnerRef" refer="t:PersonKey">
<xs:selector xpath=".//t:Vehicle"/>
<xs:field xpath="t:Owner"/>
</xs:keyref>
</xs:element>
</xs:schema>
