- From: Don Box <dbox@microsoft.com>
- Date: Thu, 31 Jan 2002 12:52:09 -0800
- To: <noah_mendelsohn@us.ibm.com>, <jacek@systinet.com>
- Cc: "Martin Gudgin" <marting@develop.com>, "XML Protocol Discussion" <xml-dist-app@w3.org>
Although, I believe that one could express all section 5-isms (typed references, arrays) using idioms currently supported in schema + a handful of NS-qualified attributes. DB > -----Original Message----- > From: noah_mendelsohn@us.ibm.com [mailto:noah_mendelsohn@us.ibm.com] > Sent: Wednesday, January 30, 2002 12:17 PM > To: jacek@systinet.com > Cc: Martin Gudgin; XML Protocol Discussion > Subject: Re: Section 5 vs Schema > > Yes, you're right, my mistake, I oversimplified the explanation of the > examples. I think we agree on the key point, which is that XML Schema is > not an appropriate description language for the directed graphs used by > the encodings. It would be easy to construct two examples that were very > different from a schema point of view, and identical per the graph model. > > ------------------------------------------------------------------ > Noah Mendelsohn Voice: 1-617-693-4036 > IBM Corporation Fax: 1-617-693-8676 > One Rogers Street > Cambridge, MA 02142 > ------------------------------------------------------------------ > > > > > > > > Jacek Kopecky <jacek@systinet.com> > 01/29/2002 08:06 AM > > > To: Noah Mendelsohn/Cambridge/IBM@Lotus > cc: Martin Gudgin <marting@develop.com>, XML Protocol > Discussion > <xml-dist-app@w3.org> > Subject: Re: Section 5 vs Schema > > > Noah, just a minor point: > > The two examples below are not precisely equivalent: > > <greeting>Hello</greeting> > <salutation>Hello</salutation> > > <greeting id="0">Hello</greeting> > <salutation ref="0" /> > > That's because in the latter, the values have some relation and > if one changes, the other does as well, while in the former > example the values are independent. I think you wanted to say > that the latter example, while a valid SOAP Encoding graph, is > not valid according to the schema provided. > > Overall, I agree with what you are saying. > > Best regards, > > Jacek Kopecky > > Senior Architect, Systinet (formerly Idoox) > http://www.systinet.com/ > > > > On Mon, 28 Jan 2002 noah_mendelsohn@us.ibm.com wrote: > > > Gudge: let me take a stab at the questions that I think you are really > > asking. There are several uses the schemas in chapter 4, that should > be > > distinguished: > > > > Derivation of simple types > > ========================== > > > > Section 4.2 [1}, for example, illustrates the use of W3C XML Schema to > > declare a derived simple type. As noted in [2], I think this may be > > appropriate insofar as the schema language is a normative W3C > > recommendation, and to clarify the possibility of using the derivation > > mechanism provided therein. What I would suggest is the following > > additions to the specification: > > > > * Make clear the validation of such types is optional, and that in the > > absence of validation we have a type whose name is known, but with > > indeterminate relation to any of the built-in types, and with any > content > > accepted (simple, complex, mixed, etc. in W3C schema terms). Contents > is > > checked only when validation is performed. > > > > * Also make clear that the use of other schema languages to declare > types > > is acceptable, but that the soap specification mandates no validation > for > > such languages either. > > > > * Make clear that when validation wrt/ any schema language is to be > > performed, it is the responsibility of the communicating nodes to agree > on > > the schema language to be used, the schemas to be used, the nature of > the > > faults to be reflected if validation fails, etc. I believe that such > > rules should apply equally to W3C schemas and to others. > > > > Other Uses of Schemas in Chapter 4 > > ================================== > > > > In section 4.2.1 [3], a schema is offered as a sample to describe the > > following instance fragment: > > > > Sample encoded instance fragment: > > <greeting>Hello</greeting> > > <salutation>Hello</salutation> > > > > Sample schema: > > <?xml version="1.0" ?> > > <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" > > xmlns:enc="http://www.w3.org/2001/12/soap-encoding" > > > > > <xs:import namespace="http://www.w3.org/2001/12/soap- > encoding" > > /> > > > > <xs:element name="greeting" type="enc:string" /> > > <xs:element name="salutation" type="enc:string" /> > > > > </xs:schema> > > > > I agree that this is misleading and inappropriate, and I suspect that > is > > the true essence of your concern. The schema is basically modeling an > XML > > tree, whereas the encoding conveys a directed label graph. Using one > to > > model the other is just inappropriate (and this by the way is one of my > > concerns about the current design of WSDL). Indeed, it obscures the > whole > > point of this section, which is that from the point of view of the > > encoding (but not the schema!), the fragment above is equivalent to: > > > > <greeting id="String-0">Hello</greeting> > > <salutation href="#String-0"/> > > > > Furthermore, as you point out, one of the main reasons to have the > > encoding at all is that the data becomes substantially self describing. > > While creating a schema for such data is not strictly wrong, I agree > that > > it does not belong in our specification. > > > > Bottom line: I think I would restrict examples using W3C XML schema to > > cases like the one in section 4.2 as discussed above. > > > > Thank you very much. > > > > [1] http://www.w3.org/TR/soap12-part2/#simpletypes > > [2] http://lists.w3.org/Archives/Public/xml-dist-app/2002Jan/0378.html > > [3] http://www.w3.org/TR/soap12-part2/#stringtypes > > > > ------------------------------------------------------------------ > > Noah Mendelsohn Voice: 1-617-693-4036 > > IBM Corporation Fax: 1-617-693-8676 > > One Rogers Street > > Cambridge, MA 02142 > > ------------------------------------------------------------------ > > > > > > > >
Received on Thursday, 31 January 2002 15:52:43 UTC