With respect to the following, is there a way to say that at least one of the attributes must be present? Otherwise, a validating XML parser cannot fully validate the document and client code has to check for null all over the place. The presence of required elements and attributes is really the most vanilla for of validity checking, and we are going to give that up if everything is nillable :-(
I realise that even then, use of xlink makes it impossible for the parser to fully validate... but it would be nice to know (from successfully parsing) that the document appears to be valid (assuming external references via xlink are to the correct kind of thing).
I think it is a nice idea to have something the client can treat as symbolic, but I'm not sure if I'd give up basic validation to get it.
Pat
On 29.11.2005 09:22, Arnold Rots wrote:
> <xs:complexType name="stcBaseType" abstract="true">
> <xs:annotation>
> <xs:documentation>STC standard base type.
> Elements of derived types may contain real content,
> be a reference to another element in the document (idref),
> or be a reference to a distributed resource;
> the href is to be a standard IVOA identifier or a valid URL.
> Actuation is up to the client.
> At this time it is required to be of type simple.
> An id is optional; it allows referencing by other elements.
> </xs:documentation>
> </xs:annotation>
> <xs:attribute name="id" type="xs:ID" use="optional"/>
> <xs:attribute name="idref" type="xs:IDREF" use="optional"/>
> <xs:attribute ref="xlink:type" use="optional" fixed="simple"/>
> <xs:attribute ref="xlink:href" use="optional"/>
> </xs:complexType>
>
> and allow the elements to be nillable.
-- Patrick Dowler Tel/Tél: (250) 363-6914 | fax/télécopieur: (250) 363-0045 Canadian Astronomy Data Centre | Centre canadien de donnees astronomiques National Research Council Canada | Conseil national de recherches Canada Government of Canada | Gouvernement du Canada 5071 West Saanich Road | 5071, chemin West Saanich Victoria, BC | Victoria (C.-B.)Received on 2005-11-30Z00:23:30