On Wed, 2004-06-23 at 08:17, Houghton,Andrew wrote:

> Over a year ago, I pointed out that MODS, and now MADS, should not
> use hard coded values in the XML schema, but instead should use
> URI's to define these types of values.  By using URI's you make
> the schema more flexible.  Other non-library communities can use
> the MODS/MADS schema with their own code lists, rather than
> extending the schema or worst creating yet another metadata
> format.  I would, again, like to encourage the use of URI's for
> code lists in MODS/MADS.

There is a down side to that flexibility, which is that changes can be
made to the list identified by the URI without any noticeable change to
the MODS/MADS schema. So anyone using MODS/MADS with those lists has to
also keep track of the updates to those lists. Right now, LC sends out
notices to the MARC mailing list (and to hard copy subscribers as well,
I believe) when lists are updated. They could probably also notify the
MODS/MADS community, but the promulgation of URI's in a variety of XML
schemas does bring up the question of how to keep people apprised of the
state of the more volatile lists so they won't be encountering frequent
unknown values.

Most hard-coded values in MODS/MADS are based on values in the MARC
records and are not highly volatile -- changes to those formats occur
slowly and deliberately.

Thus, would it be possible to have an either/and situation -- leave in
the MARC values where they are appropriate, but also allow the ability
to use a URI for expansion to other communities?
Karen Coyle
Digital Library Specialist
Ph: 510-540-7596 Fax: 510-848-3913