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>
<Model:Processes>
<Node:Process Node:template="nodeID" Node:nodeId="nodeID2">
<Node:Name Node:Comment="">Overwrite</Node:Name>
<Node:Name99 Node:Comment="">Overwrite</Node:Name99>
</Node:Process>
</Model:Processes>
Node:Process 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 Node:Process 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="Node:Process"/>
<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]

mr*****@hotmail.com (Alex Sab) writes:

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. ...
...
Node:Process 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