Schema: Change properties of inherited elements without listing them again

[Alex Sab]

Hi,
I am having trouble describing in a schema that elements can be
mandatory in one part and not mandatory in another part of the xml
document. Here is a sample xml file

<Model:Templates>
<Node:Template Node:nodeId="nodeID">
<Node:Name Node:Comment="">Name</Node:Name>
<Node:Name2 Node:Comment="">Name</Node:Name2>
...
<Node:Name100 Node:Comment="">Name</Node:Name100>
</Node:Template>
</Model:Templates>
<Modelrocesses>
<Noderocess Node:template="nodeID" Node:nodeId="nodeID2">
<Node:Name Node:Comment="">Overwrite</Node:Name>
<Node:Name99 Node:Comment="">Overwrite</Node:Name99>
</Noderocess>
</Modelrocesses>


Noderocess has exactly the same contents except that the childs are
not mandatory. I call it the "mandatory difference"

What I would like to have and can not accomplish with schemas:

1. Node:Template and Noderocess should both be Node:Node, but schema
should still state that "mandatory difference"

2. Describe in the schema the "mandatory difference" without the need
to repeat all Node:Name´s with some trick like "group, extension,
restriction, all". I tried them all but did not succeed.

I think the main problem is that changing the mandatory is only
possible in the name-elements, so changing this property always
requires to list the name-elements again. I thought the minOccurence
of the <all> element could globaly state the mandatory property but
unfortunately it did not.

Here is an example for <all>


<group name="NodeGroup">
<!--minOccurs does not help here-->
<all minOccurs="0">
<element name="Name" type="string"/>
<element name="Name2" type="string"/>
...
<element name="Name3" type="string"/>
</all>
</group>
<element name="Node" type="Node:Node"/>
<complexType name="Node">
<group ref="Node:NodeGroup"/>
</complexType>
<element name="Template" type="Node:Template"/>
<complexType name="Template">
<group ref="Node:NodeGroup"/>
</complexType>
<element name="Process" type="Noderocess"/>
<complexType name="Process">
<complexContent>
<restriction base="Node:Node">
<!--minOccurs does not help here-->
<group ref="Node:NodeGroup" minOccurs="0"/>
<attribute name="nodeId" type="string" use="required"/>
<attribute name="template" type="string" use="optional"/>
</restriction>
</complexContent>
</complexType>
<complexType name="AttrElement">
<simpleContent>
<extension base="string">
<attribute name="Comment" type="string" use="optional"/>
</extension>
</simpleContent>
</complexType>

Is there any way to accomplish this?

Alex

 

[C. M. Sperberg-McQueen]

Hi,
I am having trouble describing in a schema that elements can be
mandatory in one part and not mandatory in another part of the xml
document. ...
...
Noderocess has exactly the same contents except that the childs are
not mandatory. I call it the "mandatory difference"

What I would like to have and can not accomplish with schemas:

Well, actually, you can. What you are looking for, I think,
is that in one context an element should have one type (in
which things are mandatory), and in another the same element
(or: an element with the same name) should have a similar
type (in which things are optional). Since XML Schema
allows local bindings of element names to types, this
is not hard to do.

A simple example of the problem and some discussion of how to address
it are given at http://www.w3.org/2000/04/26-csrules.html

I hope this helps.

-C. M. Sperberg-McQueen
World Wide Web Consortium