DuCharme, Robert DuCharmR at
Thu Aug 5 15:57:12 BST 1999

>When specifying the URI for an external DTD in the DOCTYPE declaration, is
>it generally accepted that a network-accessible document should be
>specified, or a local one?  I often see examples where the URI is
><http://...> , but I find it hard to imagine that *every time* a particular
>XML file is parsed by a validating parser, the DTD is downloaded from some
>remote web server.  The XML spec does not seem to talk about this, but is
>there some search algorithm that allows a remote URI to be overridden by a
>local file, if it exists?

As far as I know, relative URIs of the form 

  <!DOCTYPE foo SYSTEM "foo.dtd">

(or some other relative path like "../dtds/foo.dtd") is more common than
using remote DTDs, although this may be changing. The beauty of allowing
relative URIs is that it makes it all backward-compatible with the SGML way,
in which URIs were not an issue. 
In XML terms, the above example points to a relative URI that is in the same
directory as the document, so if the document is local, the DTD is assumed
to be as well. 

Bob DuCharme       <bob@>  see for "XML:
The Annotated Specification" from Prentice Hall.

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