- From: Dave Reynolds <der@hplb.hpl.hp.com>
- Date: Fri, 20 Jul 2007 08:53:40 +0100
- To: Gary Hallmark <gary.hallmark@oracle.com>
- Cc: RIF WG <public-rif-wg@w3.org>
Gary Hallmark wrote: > > You think adding xpath to RIF is easier than adding generic lists and > frame types? No. But it may be easier than adding a type/class system for typed frames that is compatible with both RDFS/OWL classes and XMLSchema complex types without giving an appearance of duplication. > Does xpath have a model theory? No, I don't think so, but it is not a logic language so one wouldn't expect it to. > If it did, would it be > compatible with RIF's? Doesn't need to be. The Xpath accessors would simply be builtins working over an opaque datatype, pure side-effect-free functions, no worries :-) Dave > > Christian de Sainte Marie wrote: >> Gary, >> >> 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). >> >> During F2F6, in Innsbruck, there seemed to be broad agreement that RIF >> should not invent its own data model/schema language, as Dave and Paul >> point out. >> >> The action to "show how to use an XML schema for ADM" was seen as >> necessary because it was felt that, although several participants >> (including myself) contented that being able to use a data model >> specified in an XML Schema (or DTD) was a requirement, nobody seemed >> to have a precise idea of what it meant. >> >> As I understand it, there are basically two places where we may need >> the reference to an external, or application data model: >> >> 1. when specifying the type of a variable beyond the builtin types >> (and of a slot if we decide that RIF should allow type checking); >> >> 2. when navigating a data source, that is, to specify data accessors. >> >> As regards case 1, I suppose that a QName is all we need (in addition >> to the metadata that will tell us what this ruleset requires, e.g. a >> data model represented by an XML schema, the URI of that schema etc). >> >> As regards case 2, as I understand it, it is the 'op' property of an >> UNITERM that specifies the path to the data to be accessed, where the >> 'args' give the context. >> >> E.g., suppose that the data model is specified by the XML Schema in >> [1], and that there is a rule that says (informally) (taken from the >> MISMO POC [2]: >> >> Forall ?R: Root() >> If ?R.division="wholesale" and ?R.occupancy="Investors" >> Then r.occupancyAdjustment = 0.95d >> >> The RIF XML could be (probably not compliant with Sandro's proposed >> rules, but that is not the purpose): >> >> <Ruleset xmlns:mismo="(the URL in [1]"> >> ... >> <Rule> >> <Forall> >> <declare> >> <Var> >> <name>?R</name> >> <type>mismo:root</type> >> </Var> >> </declare> >> <if> >> <And> >> <Equal> >> <side> >> (*) Here we would like something like an XPath expr >> selecting the "division" element where the value of ?R is the context >> </side> >> <side>"wholesale"</side> >> ... >> >> (*) E.g. <Uniterm><op>mismo:division</op><arg>?R</arg></Uniterm>, >> where the arg could itself be another uniterm if we needed to navigate >> deeper; or a single 'op' could be a complete XPath expression; etc. >> The slotted syntax may be more appropriate for that case, btw. >> >> The question is: if there is a standard way, associated to the data >> model, to navigate the source - e.g. XPath if the data model is an DTD >> or XML Schema,etc -, should that be the syntax for accessors (and thus >> the syntax for accessor 'op's or slots may vary depending on the data >> model? Or does RIF need to define a RIF "data source navigation >> language" that works for, e.g., XML-S, RDF-S OWL, etc? >> >> Christian >> >> [1] >> http://anonsvn.labs.jboss.com/labs/jbossrules/contrib/apocrif/jrules/src/test/resources/xsd/mismo.xsd >> >> [2] >> http://anonsvn.labs.jboss.com/labs/jbossrules/contrib/apocrif/jrules/src/test/resources/irl/mismo2.irl >> >> >
Received on Friday, 20 July 2007 07:53:57 UTC