RE: [ACTION-331] Mappings from existing data models vs defining a new data modelling language

We should use the RIF use cases in discussions like these (as surely the
use cases are the metric we are evaluating RIF against...). Possibly we
should have a Wiki template page of use cases that can be used to
support discussions and issues as needed (sort of "score chart").

>From http://www.w3.org/2005/rules/wg/ucr/draft-20060323.html 
1.1. Negotiating eBusiness Contracts Across Rule Platforms
1.2. Negotiating eCommerce Transactions Through Disclosure of Buyer and
Seller Policies and Preferences
1.3. Collaborative Policy Development for Dynamic Spectrum Access
1.4. Access to Business Rules of Supply Chain Partners
1.5. Managing Inter-Organizational Business Policies and Practices
1.6. Ruleset Integration for Medical Decision Support
1.7. Interchanging Rule Extensions to OWL
1.8. Vocabularly Mapping for Data Integration

IMHO:
1.1-1.5 assume fixed vocabularies and therefore (one would assume)
schemas and probably XML as their fixed data technology.
1.2 and 1.4 seems more rule-without-data interchange
1.6 could be either way - possibly a semantic web app with different
schema and possibly a non-web app with different (pharma? Regional?)
schema - in the latter case I assume there is a data mapping / ontology
issue to be solved first, before comparing rules 
1.7 assumes OWL (presumably that means semantic web / RDFS?)

My 2 cents: I would alter Michael's argument to read:
> Parties are exchanging data, organised in some complex domain-specific
> schema. 

Per UC 1.1-1.5 and maybe 1.6.

> For cases where there is no predefined agreement on the
domain-specific schema, the most straightforward approach is to create
the view schema in RIF
> schema language and then map the data onto that schema using rif
rules.

And this applies to UC 1.7 and possibly 1.6.

Comments? Corrections / am I barking up the wrong tree again?

PS: I tried to persuade Christian in an off-list discussion that (for PR
RIF) we should consider not just XML/XSL but also Java object (models).
But perhaps I should let that one slide for the time being :)

PPS: have a good F2F. 

Paul Vincent
TIBCO | ETG/Business Rules 
 

> -----Original Message-----
> From: public-rif-wg-request@w3.org
[mailto:public-rif-wg-request@w3.org]
> On Behalf Of Michael Kifer
> Sent: 26 September 2007 18:49
> To: Christian de Sainte Marie
> Cc: RIF WG
> Subject: Re: [ACTION-331] Mappings from existing data models vs
defining a
> new data modelling language
> 
> 
> 
> Let me try to give a more elaborate and realistic scenario.
> 
> Parties have data to exchange, but that data is stored in some complex
> schema and they only want to exchange some part of it and in a
transformed
> form (i.e., a view, but not necessarily a database view, since
recursion
> might be involved etc.).
> 
> The most straightforward approach is to create the view schema in RIF
> schema language and then map the data onto that schema using rif
rules.
> 
> Now, regarding your description of the approach, I find it unclear.
> 
> ... The question is now: should RIF define a data schema language ...
> 
> Then
> 
> ... The benefit would be to avoid one step in the translation from/to
RIF
> ...
> 
> Benefit of what? Of a RIF schema language? I do not understand which
> beneficiary you are talking about. Then you talk about schema
languages,
> like XML. How will RIF work with XML Schema? Another layer of
> specification?
> 
> Then
>   .... In the case where no shared schema exist, the parties will have
to
> specify one and, given that RIF will provide a mapping to the main
> schema languages, they will have little motivation to choose to
specify
> that schema directly in RIF.
> 
> This is quite murky. RIF will provide mappings from which schema
> languages?
> The unknown ones that the parties agree on? Yet another level of RIF
> specification?
> 
> So, I find your conclusions unsupported, and it seems to me that you
are
> adding to the workload, not taking away.
> 
> 
> 	--michael
> 
> > All,
> >
> > In completion of my action-331, Ii will try to clarify the the issue
on
> > mappings from existing data models vs defining a new data modelling
> > language.
> >
> > I will use the term "data schema" (as in XML schema, relational data
> > base schema etc), in an attempt to avoid the confusion between the
RIF
> > data model and application specific instances of data schemas.
> >
> > I assume that the data to which the interchanged rules apply are not
> > included in the RIF document, the general cases being that either
each
> > party uses the interchanged rules with its own data, a common data
> > source is shared by different means (e.g. Web service acces), or a
data
> > document is interchanged separately (the reason for interchanging
the
> > rules and data separately, in the latter case, being to separate
> concerns).
> >
> > The problem is thus to make sure that everybody apply the rules to
the
> > data in a consistent way, that is, that, given the same dataset,
every
> > consumer of a RIF document will give the same interpretation to the
> > rules and to their parts (terms, litterals etc).
> >
> > The solution is that the parties in an interchange must agree on a
> > common data schema and on how to interpret it (in the sense that a
data
> > schema defines an application's  vocabulary -terms, relations etc-
and
> > the datasets provide the interpretations).
> >
> > Based on that agreement, each party knows how to map the data schema
> > onto their own data structure (or onto the shared data structure),
and
> > is able to apply the rules to the data in a consistent way, provided
a
> > fixed mapping between the schema language used to specify the agreed
on
> > data schema and the RIF data model.
> >
> > The question is now: should RIF define a data schema language, so
that
> > parties in an interchange can use RIF to specify the common data
schema
> > they agree on?
> >
> > The benefit would be to avoid one step in the translation from/to
RIF
> > to/from one's own rule language, as the data model would map onto
each
> > other without an intermediary.
> >
> > Without entering a theoretical discussion, nor a discussion about
> > principles, scope and, the main drawback of this approach would be
> > practical: in many cases where rules need be interchanged, if not
most,
> > the parties must interchange data for other reasons as well, or use
them
> > in a consistent way for other reason than consistent interpretation
of
> > rules, and thus need a shared data schema independently of their use
of
> > RIF for interching rules.
> >
> > Many such shared data schemas already exist, and Web languages have
been
> > designed specifically for the purpose of specifying (e.g. XML
schema).
> > In these cases, the user will be reluctant to redefine the shared
schema
> > in a different schema language, so that RIF will have to provide a
> > mapping from its data model onto the main Schema languages anyway.
> >
> > In the case where no shared schema exist, the parties will have to
> > specify one and, given that RIF will provide a mapping to the main
> > schema languages, they will have little motivation to choose to
specify
> > that schema directly in RIF.
> >
> > As a conclusion, I think that specifying a schema language within
RIF is
> > adding an unnecessary burden to our already heavy workload, and that
we
> > should focus instead on specifying how the RIF data model maps onto
> > existing and widely deployed data schema languages.
> >
> > See you in Hawthorne.
> >
> > Christian
> >
> >
> >
> 
>

Received on Wednesday, 26 September 2007 20:05:40 UTC