[tmql-wg] TMQL Proposal

Stefan Lischke lischke@ivs.tu-berlin.de
Tue, 01 Feb 2005 19:30:12 +0100


I have some points about this proposal.

In my head a topic map is represented as a graph of information items 
(defined by TMDM). For me the big advantage of topic maps is the 
abstraction in the model. We dont spend any time on thinking about "how" 
all our information items are connected. Therefor we created the 
abstract model TMDM. A Topic plays a role in an AssociationRole which is 
contained in an Association which may contain other AssociationRole. 
(plays and contains are edges)
With that i can imagine a huge topic map graph of all those TMDM defined 
information items.

But when looking at TMRQL, i have to change from a graph in my mind to a 
bunch of tables which are interconnected via id's.

The proposal says:
"One of the inherent principles that is embodied in the views approach 
is that every topic map object (topic, name, occurrence etc) has some 
kind of system identity."

That is definitely true, from the view of a Topic Map Engine developer. 
There has to be an identity for every information item.

But in my opinion it is not necessary for the user who works with topic 
maps. The user who creates a query must be able to stay in his abstract 
graph representation/imagination.

If the actual TMQL proposal fits to that needs is another question.

I researched about Graph Query Languages and subGraph Matching 
(especially efficient approaches with neural nets).

Kal maybe you can convince me. That i can stay by the graph 
representation in my mind and work with TMRQL.
How could i express the following query with TMRQL:

"Give me a subgraph of the TM, that contains a topic A, that has a path 
to topic B and C."

The problem of this query is the "path" operator, which is often used in 
Graph Query Languages. A path in a topic map is a chain of  

Such queries are very common. For example in semantic enhanced search 
engines, where you can enter the words A, B, C. You'll get all 
occurrences of the subgraph that contains A, B, C as result.

just my 2c


Kal Ahmed wrote:

> Dear all,
> Graham and I have published a paper proposing a different approach to 
> topic map querying. Rather than define a new query language, we define 
> a relational view of the topic map data model which can then be 
> queried using a standard relational query language such as SQL.
> Full details, including worked examples of the TMQL Use Cases which 
> run on TMCore05 can be found at 
> http://www.networkedplanet.com/download/TMRQL.pdf
> We would like this document to be taken as input from Networked Planet 
> Limited into the ISO TMQL standardisation process.
> Best regards,
> Kal Ahmed
> _______________________________________________
> tmql-wg mailing list
> tmql-wg@isotopicmaps.org
> http://www.isotopicmaps.org/mailman/listinfo/tmql-wg

My place : http://user.cs.tu-berlin.de/~lischke