[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: RE: Caution using XML Schema backward- or forward-compatib
> - each specifying within the WSDL the meaning of the distance What mechanism in WSDL are you expecting to be able to define semantics ? Accepting the idea that it might be possible to define schemata that provide sufficient meta-data to ensure that semantics are [less] ambiguous (i.e. your idea that the introduction of the 'method' attribute') is fair enough, but we also need to consider the case that Michael [Kay] outlined, that of 'semantic drift'. An information item that starts out with one purpose and over time drifts into other uses, and of course that very often we don't create a perfect schema in version 1.0 with all future needs catered for :-) As far as the approach of creating a new URL for what in some cases should be considered as minor revision changes (note: I don't include a semantic change as one of those), I agree, this seems to be an un-necessary overhead. Thats why I prefer to categorize changes as breaking and non-breaking where non-breaking should provide at least backwards compatibility and ideally forwards as well. Fraser. On 04/01/2008, Stephen Green <stephengreenubl@g...> wrote: > > Not using a codelist but using a method attribute seems to solve > > the problem with no need for new url. That seems to be the key. > > Add metadata everywhere in version 1. I still wonder: Is RDF/S > > going to be a valid way to do this? Would it work? It does seem > > to be becoming the standard way to add metadata for semantics. > > > P.S. > > With example > <distance>100</distance> > what meaning does this have? If it isn't clear what distance is meant > then maybe there is a need for *two* new web services: > - each specifying within the WSDL the meaning of the distance > - one for the first meaning and another for the second > - both being a distinct improvement on the first > - the original being preserved for consumer compatibility where > an attribute like 'method' might break the WSDL consumers > This just isn't likely to happen though because there might be > all sorts of similarly vague elements throughout the WSDL, each > perhaps needing new versions at some point - and a new url > or several new urls for each case just doesn't seem acceptable. > > Maybe if the attribute was not added in the first place then there > is a way to add the metadata it would have contained in another > way which doesn't break the WSDL consumers. The missing > piece seems to me to be 'tool support'. > > Maybe if OWL were used to add the metadata (as an afterthought > if an attribute like 'method' was missed from version 1) there might > be a way for a change in such metadata to trigger a signal in the > web service consumer. Perhaps that needs to be added to tools > and maybe standardization is needed too. I would love to be on the > committee deciding what to call any possible extension of WSDL > or combination of WSDL and OWL say - maybe there is a way > to call it WSDL-OWL and switch letters to make it WS-LD-OWL, > pronounced 'wise-old-owl' :-) > > I don't know enough about WSDL but when working with ebXML > I asked for an attribute 'externalDocumentDefRef' to be added to > ebXML BPSS. This, were there the tool support, could perhaps > allow a pointer to semantic metadata to be linked to a web service > via CPP/A and ebBP definitions. I would think tools would have to > detect any changes in the metadata and signal that something has > to be looked into as a thrown exception (fatal or otherwise). So > with the right ingredients in the web service, it is possible for > semantic changes to be automatically picked up by suitable tools. > > -- > Stephen Green > > Partner > SystML, http://www.systml.co.uk > Tel: +44 (0) 117 9541606 > > http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice > > _______________________________________________________________________ > > XML-DEV is a publicly archived, unmoderated list hosted by OASIS > to support XML implementation and development. To minimize > spam in the archives, you must subscribe before posting. > > [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/ > Or unsubscribe: xml-dev-unsubscribe@l... > subscribe: xml-dev-subscribe@l... > List archive: http://lists.xml.org/archives/xml-dev/ > List Guidelines: http://www.oasis-open.org/maillists/guidelines.php > >
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