Re: [topicmaps-comment] referring to a topic from outside a TM

["Thomas B. Passin" <tpassin@comcast.net>]

[Bandholtz, Thomas]

> -----Original Message-----
> From: Thomas B. Passin
...

Beeing bound to files is a legacy restriction. Topic Maps (even
PS-collections) will be very large, so they will be maintained in databases,
not in Gigabytes of XTM-files.
What about a little Java Servlet, CGI, or pl that returns a valid XTM
encoding of the topic with the given ID?

This will not position to a certain point in a probably very large document,
but it will return exactly one filtered <topic>. range in a filtered
<topicMap>. This should be a legal solution.
If you supply one URL for topic-by-id retrieval and one for
associations-by-topicid, this will give access to everything (ok, add
mergeMap).
Nobody would have to merge copies of your map into his own - this can be
merged "virtually" and distributed.

{me]
This would be easy to arrange from a programming point of view.  But
consider that you use this interface to retrieve a single topic:

<topic id='tt-flood-portsmouth-1936'>
    <baseName><baseNameString> The Great Portsmouth
Flood</baseNameString></basename>
    <instanceOf><topicRef
        link:href='http://theSourceOfTheMap.com/#tt-flood-portsmouth-1926'/>
    </instanceOf>
</topic>

It turns out that you do not have the class topic with
id='tt-flood-portsmouth-1936'.  As a person, you can read the baseNameString
of the imported topic and perhaps know what it represents (depending on the
actual name).   But your processor cannot.  It may not even be valid to
insert this topic into your map, since it references an  unknown topic.

Even if you could use the topic as is, its associations and occurrences are
probably what you really want, and they each have their own types,
superclasses, etc.  You really want a whole subgraph, but how do you know
what subgraph you want, and how do you ask for that subgraph?

The interface to get associations by topic id definitely will help, but it's
not really going to be enough, I think.  That's why I see this subject as
complicated and important.

Cheers,

Tom P