Tis Veugen wrote:


> I have a modelling problem that I would like to make clear with these 
> xml-file and xsd-file.
> 
> The xsd-file:
> 
> <xsd:simpleType name="st1">
>   <xsd:restriction base="xsd:NMTOKEN">
>     <xsd:enumeration value="v1"/>
>     <xsd:enumeration value="v2"/>
>     <xsd:enumeration value="v3"/>
>   </xsd:restriction>
> </xsd:simpleType>
> 
> <xsd:complexType name="ct1">
>   <xsd:choice>
>     <xsd:sequence>
>       <xsd:attribute name="type" type="st1" fixed="v1"/>
>       <xsd:element name="str" type="string"/>

Have you actually tried to use that schema with a validating XML parser 
or a schema parser? It would tell you that the xsd:attribute is not 
allowed inside of the xsd:sequence.

>     </xsd:sequence>
>     <xsd:sequence>
>       <xsd:element name="str" type="string"/>
>     </xsd:sequence>
>     <xsd:sequence>
>       <xsd:attribute name="type" type="st1"/>

Same here.


> The xml-file:
> 
> <my_ct type="v1">
>   <str> my other data </str>
> </my_ct>
> 
> <my_ct>
>   <str> my data </str>
> </my_ct>
> 
> <my_ct type="v2">
> </my_ct>
> 
> <my_ct type="v3">
> </my_ct>
> 
> PROBLEM:
> How to prevent that the following lines would be allowed, according to the 
> 3rd choice :
> <my_ct type="v1">
> </my_ct>
> So, how should the xsd file look like?

An W3C XML schema doesn't allow you to constraint the element content 
structure based on an attribute value.
With a Schematron schema you can model such constraints as you simply 
express them using XPath expressions:
  <http://xml.ascc.net/resource/schematron/schematron.html>

-- 

	Martin Honnen --- MVP XML
	http://JavaScript.FAQTs.com/