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Feature request for v1.1: separating enumerated vocabularies from Schemas

From: Anthony B. Coates <abcoates@TheOffice.net>
Date: Sun, 1 Dec 2002 14:54:33 GMT
To: www-xml-schema-comments@w3.org
Message-Id: <E18IVWt-0000RG-00@relay3.bt.net>

One problem that continually arises with the Schemas I work on is that there is
no simple way to separate enumerated vocabularies from the Schemas that use
them.  For example, I might have an element or attribute value that is an ISO
country code.  If the ISO country codes change, I want the latest version of
that vocabulary to be used, but I don't want to have to re-issue a new version
of the Schema just because of it (with all the relating costs of retesting,

I think v1.1 of Schema would benefit greatly from having a way of saying "this
value is one of an enumerated list of values defined externally to this
Schema".  This kind of externalisation is workable because there are no
structural implications to the changes, it is just that particular lists of
strings are allowed to evolve separately of the Schema.

In some cases, having an external file with the enumerated list of values will
be fine.  However, in the financial world there are certainly many enumerations
that are too large to physically list in a single file.  For such cases, what
is needed is a well-understood method for an application to call out to a
well-known (Web?) service to ask "is this value (or these values) part of the
current vocabulary"?  You need this facility whenever a list of enumerated
values has thousands or millions of entries (or more).

This occurs so often in the financial problems I work on that I'm sure it must
also occur all of the time in many other domains.  It would be an enormous win
if Schema could evolve the right mechanism to solve the problem, perhaps along
the lines that I have suggested here.

Anthony B. Coates, Information & Software Architect
MDDL Editor (Market Data Definition Language)
Received on Sunday, 1 December 2002 09:57:39 UTC

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