- From: Andreas Langegger <alangegger@mac.com>
- Date: Wed, 02 Jul 2008 13:01:09 +0200
- To: tim.glover@bt.com, tim.glover@bt.com
- Cc: semantic-web@w3.org
hi Tim, and what about: Person +-----------+----------+ | firstname | lastname | +-----------+----------+ | ... | | ? Or just take schemes with less inherent "common sense" than "Person". Schemas are always fixed to some certain extent, same with RDF-S. You can use OWL-DL for classification, but then at least the rules defining your classes are fixed. If we have heterogeneity (we do), we have to map, transform, etc. - I don't have a problem with this, but it's usually becoming bad when you need performance. So why is RDF better then XML? (For me) it's: global URIs and the open world assumption <- the key for Web-scale information management as well as the possibility to represent the whole graph as triples, that's great. Andy Web of Data Practitioners Days / Oct 22-23 / Vienna http://www.webofdata.info ---------------------------------------------------------------------- Dipl.-Ing.(FH) Andreas Langegger Institute for Applied Knowledge Processing Johannes Kepler University Linz A-4040 Linz, Altenberger Straße 69 http://www.langegger.at On Jul 2, 2008, at 12:25 PM, <tim.glover@bt.com> wrote: > > > I think there is a valid observation to be made about XML and RDF or > relational representations. > > Take the simplest atom of information, "There is a Person named John" > > In RDF, there is only one representation; > > <Person name John> > > In RDBMS there is only one representation > > Person > |------| > | name | > |======| > | John | > |------| > > In XML there are several possible representations, eg > > <Person name="John"/> > > <Person> > <name>John</name> > </Person> > > <Person> > <name value="John"> > </Person> > > > With more complicated data, the possible XML representations vary in > different ways, and increase exponentially w.r.t. the number of > atoms of > information. To extract the data from the XML we have to know the > detailed representation chosen. Saying we can UNION different queries > misses the point - we still have to write 3 queries. Saying we can use > transformations misses the point - we still have to write > transformations. > > The issue here is that XML fails to abstract the data from the > representation as effectively as RDF and RDBMS. In this sense, RDF and > RDBMS are better data representations than XML. > > Tim. > > > > > -----Original Message----- > From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] > On Behalf Of Bijan Parsia > Sent: 02 July 2008 10:29 > To: Olivier Rossel > Cc: semantic-web@w3.org > Subject: Re: comparing XML and RDF data models > > > On 2 Jul 2008, at 08:43, Olivier Rossel wrote: > >>> Any XML instance can be considered a compact, early-bound >>> serialization of an infoset RDF graph. >> >> +1. >> XML is very powerful when it comes to presenting data (because it >> details how data imbricate with each other). But XML is very >> unnatural > > No, please no. Don't make such claims without backup. What's > unnatural for you may be very natural to other people. And > naturalness doesn't matter if *effectiveness* is at issue. > >> when it comes to crawling the data in an unexpected and ever-changing >> manner (because XML tree structure is chosen once for all, > [snip] > > And this is just false. Google for "open content model". Look at XML > Schema's "lax" and "skip" validation modes. Consider transformations. > (I.e., many XML people are perfectly comfortable treating the "input > tree" as just one step, not a fixed one) > > RDF structure is similarly fixed in advanced (by and large). > > This kind of talk, aside from being wrong, helps marginalize the > semantic web and related technologies. > > In general, if you are inclined to make a general "betterness" claim > based on some abstract feature, don't. If you are going to anyway, > make > sure you have every detail nailed with concrete, preferably real > examples ready to hand. Even then, one is better off just presenting > the > goodness without contrast. If it's good enough, people will come. > > Cheers, > Bijan. > > > > -----Original Message----- > From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] > On Behalf Of Bijan Parsia > Sent: 02 July 2008 10:29 > To: Olivier Rossel > Cc: semantic-web@w3.org > Subject: Re: comparing XML and RDF data models > > > On 2 Jul 2008, at 08:43, Olivier Rossel wrote: > >>> Any XML instance can be considered a compact, early-bound >>> serialization of an infoset RDF graph. >> >> +1. >> XML is very powerful when it comes to presenting data (because it >> details how data imbricate with each other). But XML is very >> unnatural > > No, please no. Don't make such claims without backup. What's > unnatural for you may be very natural to other people. And > naturalness doesn't matter if *effectiveness* is at issue. > >> when it comes to crawling the data in an unexpected and ever-changing >> manner (because XML tree structure is chosen once for all, > [snip] > > And this is just false. Google for "open content model". Look at XML > Schema's "lax" and "skip" validation modes. Consider transformations. > (I.e., many XML people are perfectly comfortable treating the "input > tree" as just one step, not a fixed one) > > RDF structure is similarly fixed in advanced (by and large). > > This kind of talk, aside from being wrong, helps marginalize the > semantic web and related technologies. > > In general, if you are inclined to make a general "betterness" claim > based on some abstract feature, don't. If you are going to anyway, > make > sure you have every detail nailed with concrete, preferably real > examples ready to hand. Even then, one is better off just presenting > the > goodness without contrast. If it's good enough, people will come. > > Cheers, > Bijan. > > > Web of Data Practitioners Days / Oct 22-23 / Vienna http://www.webofdata.info ---------------------------------------------------------------------- Dipl.-Ing.(FH) Andreas Langegger Institute for Applied Knowledge Processing Johannes Kepler University Linz A-4040 Linz, Altenberger Straße 69 http://www.langegger.at Web of Data Practitioners Days / Oct 22-23 / Vienna http://www.webofdata.info ---------------------------------------------------------------------- Dipl.-Ing.(FH) Andreas Langegger Institute for Applied Knowledge Processing Johannes Kepler University Linz A-4040 Linz, Altenberger Straße 69 http://www.langegger.at
Received on Wednesday, 2 July 2008 11:02:28 UTC