Re: [tangle] getting the semweb exactly wrong

Tim Berners-Lee wrote:
> On Jan 4, 2006, at 14:23, Richard Cyganiak wrote:
>> On 4 Jan 2006, at 20:03, Tim Berners-Lee wrote:
>>> One answer is: don't!  The SemWeb is about conecting the data to  
>>> what it means.
>>> Keep the data in the place where it works and runs fast.
>>> Find/Write ontologies about what the data is about.
>>> Run a virtual RDF server (supporting SPARQL if a large DB) on top  of 
>>> the data.
>>> publish the connection between the database columns and the  ontolgies.
>> I don't get this last bit. Why would someone know what database  
>> column a bit of data comes from? Isn't this an implementation  detail 
>> that should better be hidden from consumers of the RDF?
> Sorry.  I meant define it. Don't publish it widely. But internally,  
> this mapping is
> what your code then uses to make it virtually part of the semantic web.

A few nits (which don't take away from Tim's basic point):

1.  If you're going to provide a virtual RDF server for the data, then 
it's true that the mapping between the database columns and the 
ontologies is kind of "internal".  But if you're going to provide some 
other kind of interface to the data, then it would be important to have 
the mapping from whatever is available at the interface (including the 
base columns, if that's the interface) to the ontologies, so that others 
could generate the RDF.

2.  What you'd really like to have is as complete documentation of the 
data in the underlying database as possible, not just the mappings to 
ontologies.  Lots of databases involve constraints and assumptions that 
are not necessarily expressed in available ontologies, or expressible 
in, say, OWL (having a rule language available could change that, 
depending on the capabilties of the language).  Understanding those 
constraints and assumptions could be important in properly interpreting 
the data, whether it's generated as RDF or not.  If you're providing an 
RDF interface, then by all means express those constraints and 
assumptions with respect to the RDF (and the ontologies you use).

3.  The general principles here are "any Web access is better than no 
Web access", and "any metadata is better than no metadata".


Received on Thursday, 5 January 2006 16:40:52 UTC