RE: Datamodel Strawman (ACTION-298)

+1

(With apologies as I have not checked the debate from last week's call).

My concern is re inventing Yet Another Data Representation language,
just because we have a semantic web + common data processing communities
of interest. 

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 Dave Reynolds
> Sent: 16 July 2007 09:01
> To: Gary Hallmark
> Cc: RIF WG
> Subject: Re: Datamodel Strawman (ACTION-298)
> 
> 
> [Sorry I'm going to top post rather than do a point-by-point comment
> because I seem to be suffering from context failure.]
> 
> At Innsbruck the chairs pointed out that RIF should not invent yet
> another schema language. For that reason when we adopted the Frames
> proposal several people (myself included) opposed the Classification
> proposal. Though we didn't formally reject the Classification proposal
> either.
> 
> This RIF data model seems to be based broadly on the Classification
> approach, or at least on strongly typed frames, and seems to replicate
> parts of XML Schema into RIF.
> 
> Is this necessary?
> 
> Could we just have untyped frames in RIF plus a mapping from those to
> XML, leaving all syntactic type validation to the XML schema
processing?
> 
> Or could we have a set of builtins for navigating XML data from within
> RIF (for example, XPath like)?
> 
> Dave
> --
> Hewlett-Packard Limited
> Registered Office: Cain Road, Bracknell, Berks RG12 1HN
> Registered No: 690597 England
> 
> Gary Hallmark wrote:
> > The statement for this action reads "Show how to use XML Schema for
App
> > Data Model".
> > This begs the question: what is an "App Data Model"?  I believe that
we
> > must define such a thing in RIF, and only then can we define a
mapping
> > between XML Schema (or relational databases, or OWL, or RDFS, etc.)
and
> > this RIF Data Model (RDM).
> >
> > *RIF Data Model
> >
> > *Informally, a RDM is a set of "frame types".  A frame type
specifies
> > the type (URI) of the frame and the names and types of the slots. A
slot
> > type is one of the RIF-supported XML Schema datatypes, the name of a
> > frame, or is unspecified (meaning "any type").
> >
> > *Abstract Syntax
> > *
> > class FrameType
> >     property type : Const
> >     property slots : List of SlotType
> >
> > class SlotType
> >     property name : Const
> >     subclass SingletonSlotType
> >         property type : Const?
> >     subclass ListSlotType
> >         property elementType : Const?
> >
> > At this point, I'm not exactly sure what we decided on in Innsbruck
for
> > the ASN for frames, so I'll make assumptions here:
> >
> > class Frame
> >     property oid: TERM
> >     property type: Const
> >     property slots: list of Slot
> >
> > class Slot
> >     property name: TERM
> >     property value: TERM
> >
> > *Semantics
> > *
> > A Frame's type may be the same as a FrameType's type.  If so, then
the
> > Frame's slots must agree in number, name, and type with the
FrameType's
> > slots.
> >
> > *Lists
> >
> > *XML Schemas define lots of 1-to-many relationships using the
> > "maxOccurs" attribute.  This is modeled in RDM using generic lists.
A
> > generic list has an optional type parameter to constrain the type of
the
> > list elements.
> >
> > *Friendly Syntax
> > *
> > FrameType ::= 'type' CONSTNAME '[' (CONSTNAME '->' SlotTypeName)*
']'
> > SlotTypeName ::= SORTNAME | 'list' ['<' SORTNAME '>']
> >
> > *Examples
> >
> > *type book [ author->string title->string ]
> >
> > wd1#book [ author->?X title->LeRif ]        // ?X must unify with a
> string
> >
> > type bookshelf [ contents->list<book> ]
> >
> > mybooks#bookshelf [ contents->list( wd1#book [author->Christian
> > title->LeRif] wd2#book [author->ChrisW title->"The RIF Book"]) ]
> >
> > *XML Schema
> >
> > *I believe that frame types as described above with the addition of
a
> > generic list type are sufficient to model most complexTypes of XML
> > Schema.  Additional mechanism is needed to model the "facets" of
simple
> > types such as value space restriction using enumeration, regex, and
> > numeric range restriction.
> >
> > Note the XML Schema specification is complex and "real world"
mapping
> > technologies such as JAXB 2.0 [1] have specifications that are well
over
> > 300 pages long.  It is unlikely RIF can handle all the "corner
cases".
> >
> > [1] http://jcp.org/aboutJava/communityprocess/pfd/jsr222/index.html

Received on Monday, 16 July 2007 08:41:57 UTC