[xsd-users] XSD : How to set attributes values in children element type?

[Boris Kolpackov]

Hi Klaim,

Klaim <mjklaim at gmail.com> writes:

> In an xsd file I have this element base type :
> 
> <xs:complexType name="event" abstract="true" >
>     <xs:attribute name="move" type="aos:move_ref" use="required" />
>     <xs:attribute name="type" type="aos:event_type" use="required" />
> </xs:complexType>
> 
> And I want to define the value of the type attribute in the children types,
> so I tried this :
> 
> <xs:complexType name="signal" >
>     <xs:complexContent>
>       <xs:extension base="aos:event">
>         <xs:attribute name="type" type="aos:event_type" fixed="signal" />
>         <xs:attribute name="source" type="aos:signal_source" use="required" />
>       </xs:extension>
>     </xs:complexContent>
>  </xs:complexType>
> 
> Visual Studio don't seem to bother but CodeSynthesis C++ code
> generatordon't seem to agree :
> 
> error: attribute 'type' is already defined in base

I am pretty sure CodeSynthesis XSD is correct here -- you cannot "extend"
a type to have the same attribute as is already defined in the base.


> How should I write this? I just want the value of the type attribute to be
> specific to each different child type.

What you will need is a restriction step:

<xs:complexType name="signal_base" abstract="true">
  <xs:complexContent>
    <xs:restriction base="aos:event">
      <xs:attribute name="move" type="aos:move_ref" use="required" />
      <xs:attribute name="type" type="aos:event_type" fixed="signal" />
    </xs:restriction>
  </xs:complexContent>
</xs:complexType>

<xs:complexType name="signal">
  <xs:complexContent>
    <xs:extension base="aos:signal_base">
      <xs:attribute name="source" type="aos:signal_source" use="required" />
    </xs:extension>
  </xs:complexContent>
</xs:complexType>

Boris