RE: [BIONT-DSE] Inclusion versus exclusion criteria

> The data complexity of EL++ suggest strongly that a sensible
> reduction to SQL is unlikely (i.e., you'll need datalogesque rules as
> well).

[VK] The interesting question in my mind then is what is the additional
functionality achieved by these datalogesque rules that are not present in
SQL? The reason I ask is because today the major RDBMS vendors support
transitive closure operations and I was wondering if there is any other
functionality that is missing in SQL.

Also, what would be great is to get a concrete real world example which
illustrates the above. The example given by Kavitha, I believe has a SQL
translation. Getting such examples are crucial to showing the value of the web.

> Even logspace data complex logics can be tricky. The DL-Lite family
> is the paramount example and they can have an exponential blowup in
> the size of the query (since they need to intern parts of the tbox in
> the query, so each conjunct might expand, and then the permutations
> of the expansions must be added to the union of queries...er...as I
> recall :))

[VK] From a pragmatic point of view, in the context of a given application, 
this just needs to be done once. There are well defined RDBMS approaches to
create views, materialize them, develop indexing structures to achieve
scalability.

For instance, I know that a common approach to using Snomed is to precompute
the "closure" and store it in a RDBMS.

So, the real world has figured out ways of dealing with these situations and
I am yet to see examples of how using semantic web technologies, will give them
the scalability and make their life easier.

> So, basically, large queries with large, connectd TBoxes will be
> challenging, requiring clever optimization of the rewriting. This
> isn't something you'll do by hand ;)

[VK] Can I have some real world examples which illustrate this?

---Vipul


The information transmitted in this electronic communication is intended only for the person or entity to whom it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this information in error, please contact the Compliance HelpLine at 800-856-1983 and properly dispose of this information.

Received on Thursday, 13 September 2007 12:40:57 UTC