[sc34wg3] TM Data Model issue: prop-subj-address-values

Geir Ove Grønmo sc34wg3@isotopicmaps.org
23 Oct 2003 16:02:35 +0200

I have a comment on the latest TMDM commitee draft dated 2003-10-22.

The [subject addresses] property on the topic item has been renamed to
[subject locator]. I agree with the name change, but I'm rather
sceptical of it no longer being a collection property. A consequence is
the following constraint:

Constraint: Subject locator collision

   Two topics being merged cannot have different values in their
  [subject locator] properties.

This constraint prohibits automated merging of topic maps in the cases
where two topics are bound to be merged based on identity, e.g. when
they have subject indicators in common, but the two have different
subject locators.

It looks to me that only a human being can resolve such an issue. This
is extremely unfortunate and inconvenient. The two topics have after all
been considered to be the same topic because of their other identities.

If a topic had more than one subject locator the subject locators
should of course all reference the _same_ information resource. In my
opinion it is only a problem when it can be _proved_ that they are not
the same information resource. There could be many reasons why an
information resource could have more than one valid locator.

What was the rationale for the change in the draft?

Geir O.