W3C home > Mailing lists > Public > public-rif-wg@w3.org > August 2007

Re: presenting data models in RIF

From: Gary Hallmark <gary.hallmark@oracle.com>
Date: Tue, 21 Aug 2007 15:50:41 -0700
Message-ID: <46CB6C41.6080204@oracle.com>
To: Dave Reynolds <der@hplb.hpl.hp.com>
CC: Chris Welty <cawelty@gmail.com>, Michael Kifer <kifer@cs.sunysb.edu>, RIF WG <public-rif-wg@w3.org>

Dave Reynolds wrote:

> Do rules themselves need to access the data model not just the data?

rules need access to data and relationships.  For example, I expect a 1 
to many relationship between purchase orders and line items, and I 
expect to be able to express a condition in a rule about a purchase 
order and its related line items.
The rules I've seen in RIF access relations and frames, not XML data nor 
RDF data nor Java data.  If I plan to interchange some rules in RIF and 
a data model in an XML schema, I'd also need some mapping information 
that shows some kind of correspondence between schema definitions and 
frames and relations.  How do I "bind" frames and relations in RIF to 
types and relationships in XML schema?  Given an element 
"http://someplace/line-item" and another element "http://someplace/po" 
that contains a sequence of 0 or more line-item elements, how do I write 
rules about po/@num = 123 and its related line-items?  What are the 
frames? slots? Association between po and its related line-items?

> In the case of semantic web applications then yes, but that's not a 
> problem since RDFS/OWL are themselves encoded in RDF so an RDF access 
> mechanism is sufficient.
> I haven't heard any use cases for accessing the model itself in the 
> XML or object cases. Gary presented a case (car/lorry/vehicle) for 
> there *being* a data model but the rules seemed to only need to 
> consult the type of instances not the hierarchy or domain/range 
> constraints themselves). I understood Paul to be saying that direct 
> access to the schema from the rules would be unusual in the business 
> rule setting.
> As a way to make progress I would find it helpful to get more use 
> cases from the commercial vendors on how data models are exchanged at 
> the moment and why a new RIF data model interchange would help. Based 
> on things like the URC document section on processing models I had 
> been under the impression that the dominant approach, outside RDF/OWL, 
> was to define the data model in XML Schema and don't really see how 
> the existence of a new class hierarchy relation is of significant 
> benefit in processing data defined in such a way.
> Dave
> [Unfortunately I won't be able to make the next telecon.]


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Gary Hallmark | Architect | +1.503.525.8043
Oracle Server Technologies
1211 SW 5th Avenue, Suite 800
Portland, OR 97204
Received on Tuesday, 21 August 2007 22:50:47 UTC

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