Actually, there is not, to my knowledge, a one-to-one relationship
between target namespaces and schemas. For example, versions 3.0
through version 3.3 of MODS all declare the same target namespace:
http://www.loc.gov/mods/v3. But each is represented by a different
schema (or version of the mods schema). The case is even more complex
for xlink, for which there is no normative schema--users have been left
to role their own implementations of xlink. But as far as I know, all
implementations of xlink are supposed to be declaring the same target
namespace regardless of the particular implementation of xlink they
reference. Initially the MODS and METS schemas imported different
xlink schemas, although each was identified by the same target
My initial question has little, if anything, to do with the target
namespace URI--but rather with the very issue that Karen brings up in
her response to my original query.
[log in to unmask]"
From: Metadata Object Description Schema List [mailto:[log in to unmask]] On
Behalf Of Karen Coyle
Sent: Friday, March 13, 2009 4:53 PM
To: [log in to unmask]
Subject: Re: [MODS] URL for the current version of mods
Andrew, it sounds like you are saying that there shouldn't be a generic
URL... ? I believe that people asked for it in the past, but maybe it's
not a good idea. It seems to work when updates are backward compatible
but not when they aren't.
No I'm not saying that there should not be a generic URI to the MODS
XML schema. Having a generic URI is useful especially when you want to
link to the latest specification. However, I was saying that:
1) The generic cannot be used in the xsi:schemaLocation attribute for
MODS instance documents because the attribute uses a specific MODS
namespace and the XML schema returned by the generic URI could be
any MODS namespace. There is a one-to-one relationship between a
namespace and its schema.
2) The LC web site does not indicate that the MODS generic URI is a URI
alias of the latest MODS XML schema and use appropriate HTTP status
codes and headers to indicate that the generic URI is returning the
representation of the latest MODS XML schema.
These two issue, I believe, led to the confusion of the original poster
asking whether they should or should not be using the generic URI in
the xsi:schemaLocation attribute in their MODS instance documents.
Software Engineer, Research and Development
U.C. Berkeley Library
88 Herrada Rd
Santa Fe, NM 87508