- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Tue, 25 May 2004 13:27:45 +0100
- To: "Thompson, Bryan B." <BRYAN.B.THOMPSON@saic.com>, "''public-rdf-dawg@w3.org' '" <public-rdf-dawg@w3.org>
-------- Original Message -------- > From: Thompson, Bryan B. <mailto:BRYAN.B.THOMPSON@saic.com> > Date: 25 May 2004 13:13 > > Andy, > > You wrote: > > > If that bridge is a way to extract information from RDF models and > > get it into both XHTML (for people) and XML (for people and for > > web services), then I agree with you. > > Variable bindings certainly seem to be a good place to start in order > for the client to be able to avoid posing the query twice - once to > the RDF store and once to the identified sub-graph (and possible using > a different kind of query interface altogether!) > > So, can you outline for me how you see that variable bindings exposed > by a DAWG protocol could be exploited by an XML Stylesheet so as to > generate, e.g., an XHTML document? > > -bryan Rather than an on-the-fly design, how about from the examples of systems that have tried this: --------------------- From: http://rdfweb.org/people/damian/treehugger/introduction.html Treehugger example: <xsl:for-each select="./rss:items/rdf:Seq/rdf:li/rdf:Resource"> ... do something with each member of the sequence ... </xsl:for-each> A path is Treehugger is property/class/property/class - I prefer a property/property/property path but that isn't relevant here. So make/replace the "select" attribute be a graph pattern. Need to cope with multiple variables in the query string. --------------------- From Jonathan Robie's talk: http://www.w3.org/2004/Talks/tp-robie/slide4-0.html declare namespace rdf = "rdf.tagsalad.org"; for $artist in rdf:instance-of-class(rdf:predicate-domain("c:creates")) let $artifact := rdf:join-on-property($artist, "c:creates"), $museum := rdf:join-on-property($artifact, "c:exhibited") return <result> <artist>{ $artist }</artist> <artifact>{ $artifact }</artifact> <museum>{ $museum }</museum> </result> --------------------- Can one write in Xquery: $var1 $var2 := someQueryFunction("graph pattern") If so, then this would be a more compact form. Bryan - is this what you had in mind? Andy > > -----Original Message----- > From: Seaborne, Andy > To: Thompson, Bryan B.; 'public-rdf-dawg@w3.org' > Sent: 5/25/2004 6:39 AM > Subject: RE: Building a bridge from RDF to the web? > > > From: Thompson, Bryan B. <> > > Date: 24 May 2004 20:49 > > > > One of the issues that became clear to me during the recent WWW > > meeting in NYC is that we are missing a bridge between the RDF model > > and XML. In particular, people who are going to be using the semantic > > web need a bridge from the RDF data model to application specific XML > > vocabularies (actually, we need one that goes the other way also, but > > that is, I think, a seperate question). Perhaps the most common use > > case is querying an RDF resource and using the results to drive an XSL > > Transform, which in turn might generate XHTML. > > If that bridge is a way to extract information from RDF models and get > it > into both XHTML (for people) and XML (for people and for web services), > then > I agree with you. There isn't going to be one such form for presenting > information extracted from RDF so tools such as XSLT and XQuery seem to > be > the toolsets to use. > > There has been some work on this: Rob outlined the use of XQuery and OWL > data, and it reminded me of Jonathan Robie's presentation [1] at Cannes > this > year. The important aspect here is that access is to the abstract > graph, > not the RDF/XML syntax. > > Elsewhere, Howard talked about using paths to access the graph and > Treehugger [2] does this by dymanically materialising an XML document > from > the RDF abstract graph. > > This is getting stuff out of RDF. The requirement it places on the WG, > as I > see it, is to produce a format for variable bindings that is easily > digestable by other systems. That does not automatically mean an XML > format > because it is the output of XQuery functions but an XML format would > work > (it can be made streamable which RDF isn't). > > I have also seem people do queries in JSP taglibs to produce HTML and > also > using Velocity to create XHTML from RDF - a standard library to do the > variable bindings to Velocity > > > > > This issue has been more or less discussed in the context of > > templates, which did not receive strong support at the first f2f as a > > requirement for DAWG. > > IIRC the "Templates" discussion was slightly different. Its about > constructing new RDF from information pulled from existing RDF. See the > SeRQL 'construct' [3] operation or "cwm --filter". > > > However I think that NOT having this is going to be a major > > stumbling block for adoption of the DAWG recommendation by application > > developers and is going to make it very difficult to get at that sense > > of loose coupling and content reuse that makes the web so exciting. > > > > I would like to get a sense from people of how a DAWG spec could best > > facilitate this. Do we need to do this ourselves? Can we expose the > > data model query language in such a way that it can be usefully > > applied by XSL Transforms? Should this be considered out of scope > > for the charter? > > > > Thanks, > > > > -bryan > > [1] http://www.w3.org/2004/Talks/tp-robie/ > [2] http://rdfweb.org/people/damian/treehugger/ > [3] http://www.openrdf.org/doc/users/ch05.html#d0e1101
Received on Tuesday, 25 May 2004 08:28:22 UTC