- From: Richard H. McCullough <rhm@PioneerCA.com>
- Date: Tue, 1 Jul 2008 12:38:29 -0700
- To: "Bijan Parsia" <bparsia@cs.man.ac.uk>, "Maciej Gawinecki" <mgawinecki@gmail.com>
- Cc: <semantic-web@w3.org>
What you really need is a language like mKR (http://mKRmKE.org/) Given any thing, X, in a knowledge base X has ?; # displays all attributes of X X do ? done; # displays all actions of X X isc* ?; # displays subhierarchy of X X isa* ?; # displays all classes of X, up to Thing. Dick ----- Original Message ----- From: "Bijan Parsia" <bparsia@cs.man.ac.uk> To: "Maciej Gawinecki" <mgawinecki@gmail.com> Cc: <semantic-web@w3.org> Sent: Tuesday, July 01, 2008 3:53 AM Subject: Re: comparing XML and RDF data models > > On 1 Jul 2008, at 11:21, Maciej Gawinecki wrote: > >> In one of the article comparing two data models: XML and RDF I >> found a statement stating that (I'm loosely citing from my memory): >> >> Searching XML with XPath query expression is easy if you know the >> schema of the document being quiried. > > I don't think that knowing the schema is remotely necessary. XPath is > not schema aware, for example. I'd hazard that most XPath is over > merely well formed XML. > > You do need to know something about the structure, but, for example, > it's pretty easy to use ancestor and descendent queries to ignore > quite a bit of structure. > >> However, the same query will not >> work any a document, which is differently structured, but contains >> equivalent information. > > If the structure is *far* enough away, then of course. If you renamed > everything and leave the structure intact, this is true too. It's > also true for RDF> > >> This can be solved by usage of RDF model, >> which can be then queried with RDQL or SPARQL query. >> >> Is that really true, that XPath-based XML search is limited due to >> its structure? > > In a restricted sense, yes. > >> Yes, that's why there is a great research on keyword-based quering >> of XML documents (not knowing schema in advance). > > This won't help if names change (which is a kind of structural change). > >> But is it RDF really better for this issue ? > [snip] > > Not even a little bit. > > Consider changing from a data valued property to an intermediate > object. I.e., > > s weighs "10". > > to > s weighs _:x. > _x: weightvalue "10". > _x: atTime "...". > > You have to change the query in SPARQL. In XML it's pretty easy to > maintain your xpath, e.g., > > <Weight name="S" value="10"/> > > vs > > <Weight name="S" value=10 timeRecorded="..."/> > > The same xpath will get the name and value. > > Of course if you shift from attributes to elements, you'll have made > too big a structural change for that xpath. But so? > > Bijan. > > > Dick McCullough http://mKRmKE.org/ Ayn Rand do speak od mKR done; knowledge := man do identify od existent done; knowledge haspart proposition list; mKE do enhance od "Real Intelligence" done;
Received on Tuesday, 1 July 2008 23:12:20 UTC