W3C home > Mailing lists > Public > semantic-web@w3.org > June 2007

Re: Is there a way to specify a data format based on RDF ?

From: Dan Brickley <danbri@danbri.org>
Date: Thu, 14 Jun 2007 13:09:44 +0100
Message-ID: <46713008.9050305@danbri.org>
To: Dave Reynolds <der@hplb.hpl.hp.com>
CC: Andrea Splendiani <andrea.splendiani@univ-rennes1.fr>, SW-forum <semantic-web@w3.org>

Dave Reynolds wrote:
> 
> Andrea Splendiani wrote:
>>
>>>> RDF just isn't well suited for describing structures that MUST  
>>>> include a particular field.  (You *can* do this, but then you're  
>>>> ignoring RDF's semantics, and just treating it as a weird database).
>>>
>>> Additional assumptions are not quite the same as ignoring the 
>>> semantics :-)
>>>
>>> In engineering terms there is often a point where you have to say
>>> "whilst the world is open this is all the data I'm actually going to
>>> get and I have to check if this data is complete enough to meet the
>>> assumptions of my next processing step". That doesn't stop you
>>> benefiting from the flexibility of the open world assumption right up
>>> to the point where you have perform a closed-world model check in order
>>> to proceed (e.g. actually send a message to that address).
>>
>> Yes and...
>> is there a way to formalize these extra contraints ?
>> If I want to provide a documentation about them, to define an exchange 
>> message ? Or a post-pre-requisite valid "content" ?
> 
> I was suggesting using OWL restrictions (esp. cardinality and hasValue 
> restrictions) and performing closed-world model checking on your data 
> against that OWL.
> 
> Other than integrity rules (for which there is no semantic web standard) 
> then another approach would be to perform schematron-style syntactic 
> validation by specifying SPARQL queries which should or should-not 
> return results from querying the message.

I'm pretty enthusiastic about this design, though in fairness I must 
admit to not having yet built much on top of it. Libby Miller and I were 
experimenting with this a while back, 
http://ilrt.org/discovery/2001/02/schemarama/ but post-SPARQL the idea 
has a lot more force, since we have a standard QL with optionals, 
datatype-related functionality, etc. More recent long rambly post here,
http://danbri.org/words/2005/07/30/114  and some work in the same 
direction from Alistair Miles here: 
http://isegserv.itd.rl.ac.uk/blogs/iseg/schemarama/

I've heard rumour that the ISO version of Schematron (publically 
available, 
http://isotc.iso.org/livelink/livelink/fetch/2000/2489/Ittf_Home/PubliclyAvailableStandards.htm 
  ) has something of a plugin design, so it might be possible to package 
SPARQL queries directly in the Schematron XML format. Ah, yup

[[
Annex F
(normative)
Use of Schematron as a Vocabulary
The following Schematron element types may be used as vocabulary 
elements by other standards and schemas.
The semantics of element types used externally shall follow this part of 
ISO/IEC 19757.
 schema
 pattern
 rule
 assert
 report
These elements should use the standard Schematron namespace specified in 
5.2.
When Schematron elements other than the schema element are used as 
vocabulary elements by other standards
and schemas, the other standard or schema should specify mechanisms for 
defining information otherwise supplied
by Schematron elements, such as ns or let.
]]

...has anyone taken a closer look at this possibility?

cheers,

Dan
Received on Thursday, 14 June 2007 12:09:57 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 07:41:57 UTC