- From: Dan Connolly <connolly@w3.org>
- Date: 04 Feb 2002 11:15:01 -0600
- To: Brian McBride <bwm@hplb.hpl.hp.com>
- Cc: RDF core WG <w3c-rdfcore-wg@w3.org>
On Mon, 2002-02-04 at 07:00, Brian McBride wrote: > An updated summary of the datatyping issues, as I currently understand them. > > Changes: > > B1 now disputed > B7 status changed to agreed > B9 withdrawn > B10 added "say what you mean" > > Issue B1: > ========= > > status: disputed by Sergey. Sergey you owe us an explanation of why. Perhaps Sergey's position is the same as mine... > In S, if one wants to use both idiom A and idiom B, e.g. > > <mary> <age> "10" . > <age> <rdfs:range> <xsd:integer.lex> . > > and > > <mary> <ageD> _:a . > _:a <xsd:integer.map> "10" . > > two properties have to be used, <age> and <ageD>, in this example. Yes, *if* one wants to use both idioms, one needs both sorts of properties. But I don't think most communities want to use both idioms. For example, I expect Dublin Core (and maybe prism?) to recommend S-B exclusively; hence they only need <age>, not <agedD>. > I believe there is a agreement that this is a difference between the > two proposals. Indeed, it may be said that the main aim of TDL is > to avoid requiring different properties for these different idioms. [Brian, you asked *why* I hold the position I do; I'm just about to get on an airplane, so I'm not likely to be able to phone you as you requested; I don't mind sharing my motivation with the WG, so...] Yes, TDL seems to be an attempt to allow folks to use the name of something (e.g. "10") as that something (the integer after 9). I know that folks want to do this; they want to write <book> dc:author "Dickens". and <book> dc:author _:x. _:x contact:familyName "Dickens". interchangeably. The bad news is: computers don't handle this sort of ambiguity the way people do. The TDL proposal may solve this problem for a privileged few classes (the XML schema datatypes) but it does not solve it for people, places, and other sorts of things. So it's harmfully misleading. > Issue B5: Storage Requirements > =============================== > > status: disputed. > > TDL requires significantly more storage to implement. Sergey got back on this one, no? In short: you may not need to store the whole string lots of times, but you do need to store some sort of distinct identity for each occurence of a string. [my ride to the airport arrives...] > > > Issue B6: S requires 4 URI's be registered for each data type > ============================================================= > S requires that for each datatype 4 URI's be registered > datatype > datatype.lex > datatype.val > datatype.map > > Sergey: Do you agree this is the case? If not, how many URI's are required > to implement ALL the idioms of S and coexist in the same model. > > > Issue B7: Complexity > ==================== > > status: agreed > > S has several ways of expressing the same thing. An RDF processor has to be > aware of them all. Supported by Jeremy's error cases message > > http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0397.html > > and a message from Andy Seaborne to rdf comments: > > http://lists.w3.org/Archives/Public/www-rdf-comments/2002JanMar/0058.html > > > Issue B8: S-B encourages logically (sic) errors in the > application type processing. > ======================================================= > > status: ? > > Given: > > _:f <rdf:type> <film> . > _:f <dc:Title> "10" . > <mary> <age> "10" . > > an application 'knows' that the range of <age> is an integer so it 'knows' > that mary has <age> 10. Under S-B, running a query: > > ?x <dc:Title> ?y . > ?z <age> ?y . > > will return ?x = _:f and ?z = <mary>, and knowing that the age of <mary> is > 10, may conclude that the title of the film is also 10. > > Can't Live With: Jeremy > > > Issue B9: In TDL a document does not entail itself > ================================================== > > status: Withdrawn. > > Under TDL, does: > > <foo> <dc:Title> "W3C" . > > entail > > <foo> <dc:Title> "W3C" . > > yes. > > > Issue B10: Say what you mean > ============================ > > status: ? > > The concern here is that in TDL, a literal denotes a pair consisting of a > value and a lexical representation of that value. The problem is then that > the german representation of floating point number, e.g. "10,5" is > different from the english representation, e.g. "10.5". > > Thus under TDL a german 10 and a half is a different thing from an english > 10 and a half. > > > More formally, under TDL: > > <foo> <eg:size> _:s1 . > _:s1 <rdf:value> "10,5" . > _:s1 <rdf:type> <xsd:double-de> . > > <bar> <eg:size> _:s2 . > _:s2 <rdf:value> "10.5" . > _:s2 <rdf:type> <xsd:double> . > > does not entail: > > <foo> <eg:size> _:s . > <bar> <eg:size> _:s . > > Does anyone dispute the facts, or that this is a significant issue? > > > > > > > > -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Monday, 4 February 2002 12:15:59 UTC