sub-documents

Michael Ewins (mik@owl.co.uk)
Fri, 11 Dec 1998 15:14:41 -0000

I have a structure that I am trying to model using XML but I want to be able to
split the main document into a number of sub-documents. I have seen a brief
description of using sub-documents in "Structuring XML Documents" by David
Megginson but it doesn't cover the problem I'm trying to solve nor does it go
into much detail w.r.t. how to define the appropriate DTD.

The example DTDs and documents shown below are an attempt to explain what I'm
trying to do. I want to use the element B in the document "A" and the document
"B-DOC". Is this possible with the structure defined below or should I be using
another mechanism?

** "a.dtd"
<!DOCTYPE A [
<!ELEMENT A ( B | B-PTR)* >
<!ELEMENT B (EMPTY) >
<!ATTLIST B value CDATA #REQUIRED >
<!ELEMENT B-PTR (EMPTY) >
<!ATTLIST B-PTR src CDATA #REQUIRED >
]>

** "bdoc.dtd"
<!DOCTYPE B-DOC SYSTEM "a.dtd" [
<!ELEMENT B-DOC ( B*) >
]>

** doc1.xml
<A><B value="1"/><B-PTR src="doc2.xml"/><B value="4"/></A>

** doc2.xml
<B-DOC><B value="2"/><B value="3"/></B-DOC>

And as a follow-up question... would it be better to define the element B in the
bdoc.dtd and re-use it in a.dtd?

Thanks in advance for any help...

--
Michael Ewins
Office Workstations Ltd -- mik@owl.co.uk -- http://www.owl.co.uk