XML: is there an "xml-include"

Bryan Heidorn heidorn at ALEXIA.LIS.UIUC.EDU
Tue Nov 20 15:00:46 CET 2001

At 11:17 AM 11/20/01 +0100, you wrote:
>If character are defined with an id (numeric or character) in one
>file, and the item descriptions use these ids through idref or
>through xml-schema keyref means:
>How can a validating parser validate the schema, including keyrefs,
>without having to include the entire character definition in each of
>1000s of taxon description xml files? Can the ids for idref/keyref be
>declared to be in a separate file?

The character definition for a class of taxa, including the list of valid
states could be included as part of the character-schema. An "include" can
be used to insert the character schema within a taxon schema. The character
schema would allow the validator to enforce the limitations on any
particular xml instance file. As pointed out by Kerry Barringer I do not
believe that there is a need in XML to use an additional level of
indirection to include the item definitions in another file. This will cost
space but there is nothing to keep the XML from being stored in a
relational database and constructed on the fly as needed. If we want to
enforce relational normalization it might best be done in the underlying
database not in the xml instantiation of a view of the data.

It might be cleaner if the XML validator could do this but for the purposes
of data interchange and even interoperability, I think it is still useful
for the xml validator to be able to check the xml documents even without
the relational constraints. What is lost is that if you are moving data
from one database to another, a program might not be able to easily
recognize data relations and the receiving database might inefficiently
save the data in a different database structure from the originating database.

Bryan Heidorn

>I could not find a standard xml-include command. I know there is one
>defined for dtds, but that is all I could find.
>Can the xml experts help?
>PS I will post minutes of the TDWG meeting within the next days
>Gregor Hagedorn (G.Hagedorn at bba.de)
>Institute for Plant Virology, Microbiology, and Biosafety
>Federal Research Center for Agriculture and Forestry (BBA)
>Koenigin-Luise-Str. 19          Tel: +49-30-8304-2220
>14195 Berlin, Germany           Fax: +49-30-8304-2203
>Often wrong but never in doubt!

   P. Bryan Heidorn    Graduate School of Library and Information Science
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