Martin Honnen wrote:
> 
> 
> Victor Engmark wrote:
> 
>> How do I define that the contents of an element should be unique only 
>> in a sub-tree of the whole XML file?
>>
>> In my case, I have several documents, each containing several files. 
>> The file names have to be unique only within each document. I.e., the 
>> following is valid:
>> <doc>
>>     <file>AAA</file>
>>     <file>BBB</file>
>> </doc>
>> <doc>
>>     <file>AAA</file>
>> </doc>
>>
>> , while the following is not:
>> <doc>
>>     <file>AAA</file>
>>     <file>BBB</file>
>>     <file>AAA</file> <!-- Matches previous file! -->
>> </doc>
> 
> 
> XML schema allows for uniqueness constraints, here is an example schema
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
> 
> <xs:element name="root">
>   <xs:complexType>
>     <xs:sequence>
>       <xs:element ref="doc" maxOccurs="unbounded" />
>     </xs:sequence>
>   </xs:complexType>
> </xs:element>
> 
> <xs:element name="doc">
>   <xs:complexType>
>     <xs:sequence>
>       <xs:element name="file" type="xs:string" maxOccurs="unbounded" />
>     </xs:sequence>
>   </xs:complexType>
>   <xs:unique name="uniqueFile">
>     <xs:selector xpath="file" />
>     <xs:field xpath="." />
>   </xs:unique>
> </xs:element>
> 
> </xs:schema>
> 
> and an example document
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>       xsi:noNamespaceSchemaLocation="test20040430Xsd.xml">
>   <doc>
>       <file>AAA</file>
>       <file>BBB</file>
>   </doc>
>   <doc>
>       <file>AAA</file>
>       <file>AAA</file>
>   </doc>
> </root>
> 
> where the validation will flag an error for the second <file> element in 
> the second <doc> element.

I tried this, but I have obviously overlooked something, because the 
file http://vengmark.home.cern.ch/vengmark/moi/examples/input.xml is 
valid according to 
http://vengmark.home.cern.ch/vengmark/moi/examples/moi.xsd, even though 
none of the ID elements are unique. Sorry the example is verbose...

-- 
Victor