Lars,
I think that the granularity of Guy's comment was directed at a normalized
RDBMS
schema that encodes the assertions found in a topic map document. Of course
the
behaviors (semantics) of those topic map assertions still need to be
implemented
for a processor to be a "topic map processor".
Consider a service that translates a topic map document, e.g., XTM, into
this
internal model and the re-serializes it, e.g., as a "consistent topic map"
using
the XTM syntax. I would say that this is a "topic map processor". Guy made
the
point that the internal model for the processor could be a set of reified
triples.
Perhaps this was one of the points of the topic maps reference model (or the
topic maps processing model) -- that you can re-represent the XTM syntax as
a
set of assertions using an ARCx (assertion node, role node, casting node,
player
node). In this context you can see how the ARCx model can be readily
aligned
with the RDF model as a reified triple, which is what Guy was suggesting
below.
-bryan
-----Original Message-----
From: topicmapmail-admin-Zo64W7twoUFWk0Htik3J/w@xxxxxxxxxxxxxxxx
[mailto:topicmapmail-admin-Zo64W7twoUFWk0Htik3J/w@xxxxxxxxxxxxxxxx] On Behalf
Of Lars Marius Garshol
Sent: Tuesday, December 16, 2003 11:08 AM
To: topicmapmail-Zo64W7twoUFWk0Htik3J/w@xxxxxxxxxxxxxxxx
Subject: Re: [topicmapmail] TM and RDF/S
* Guy A. Lukes
|
| But in my resent attempt (with Bryan Thompson) to implement a topic
| map in a relational database, I was shocked to discover that the
| underlying database structure was only a slight modifications of RDF
| triples.
|
| The Subject is the a-node
| The predicate is the r-node
| The object is the x-node
|
| All that was missing was a c-node to reify the triple
| and a set of PSIs to implement subject roles
| (predicates/r-nodes/roles) to support topicmap merging behavior.
|
| This gives you the simplicity of the semantics free RDF triples, with
| the power of topicmap subjects and merging (if you need it), plus the
| ability to leverage all work that is going on in the RDF community.
|
| Is there something I am missing, that is going to cause be problems
| down the road?
Well, what you describe here does not have any obvious resemblance to topic
maps as they are described in ISO 13250:2000 or ISO 13250:2003, nor to
anything that is currently scheduled to go into the next edition of ISO
13250. In short, it's not clear that what you describe here could be called
topic maps. It certainly does not follow any published standard by that
name.
Also, what you describe sounds like the Topic Maps Reference Model, and
while I am no expert on the RM it does sound to me like you may have omitted
parts of it. We'd need to see the RDBMS schema to be sure, of course, but
that's my impression.
--
Lars Marius Garshol, Ontopian <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50 <URL: http://www.garshol.priv.no >
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