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RE: [Issues] WSDL and INLINE Schema Definitions

From: Martin Gudgin <mgudgin@microsoft.com>
Date: Sun, 8 Sep 2002 15:45:05 -0700
Message-ID: <92456F6B84D1324C943905BEEAE0278E01FC649C@RED-MSG-10.redmond.corp.microsoft.com>
To: "Sanjiva Weerawarana" <sanjiva@watson.ibm.com>, <asirv@webmethods.com>, "Web Service Description" <www-ws-desc@w3.org>
Cc: <prasad.yendluri@webmethods.com>

We should add these to the issues list.

I think I'd also like to suggest that importing SCHEMAS using
wsdl:import should be disallowed. If someone wants to import a schema
then they should do

<wsdl:types>
  <xsd:schema>
    <xsd:import namespace='...' />
  </xsd:schema>
</wsdl:types>

Gudge

> -----Original Message-----
> From: Sanjiva Weerawarana [mailto:sanjiva@watson.ibm.com]
> Sent: 07 September 2002 07:25
> To: asirv@webmethods.com; Web Service Description
> Cc: Martin Gudgin; prasad.yendluri@webmethods.com
> Subject: Re: [Issues] WSDL and INLINE Schema Definitions
> 
> 
> +1 to all the resolutions proposed by Gudge below.
> 
> Sanjiva.
> 
> ----- Original Message -----
> From: "Asir S Vedamuthu" <asirv@webmethods.com>
> To: "Web Service Description" <www-ws-desc@w3.org>
> Cc: "Martin Gudgin" <mgudgin@microsoft.com>;
> <prasad.yendluri@webmethods.com>
> Sent: Friday, September 06, 2002 11:10 PM
> Subject: [Issues] WSDL and INLINE Schema Definitions
> 
> 
> >
> > With permissions from Martin (thank you !!), I am posting
> this thread
> > to
> the
> > WSDesc WG. Please review and address them as appropriate.
> >
> > Regards,
> >
> > Asir S Vedamuthu
> >
> > webMethods, Inc.
> > 703-460-2513 or asirv@webmethods.com http://www.webmethods.com/
> >
> >
> > -----Original Message-----
> > From: Martin Gudgin [mailto:mgudgin@microsoft.com]
> > Sent: Friday, September 06, 2002 5:20 AM
> > To: asirv@webmethods.com
> > Subject: RE: Challenges raised by INLINE Schema Definitions
> >
> >
> > [inline]
> >
> > > -----Original Message-----
> > > From: Asir S Vedamuthu [mailto:asirv@webmethods.com]
> > > Sent: 05 September 2002 15:35
> > > To: Martin Gudgin
> > > Subject: FW: Challenges raised by INLINE Schema Definitions
> > >
> > >
> > > Martin,
> > >
> > > What are your thoughts on this? Thank you.
> > >
> > > Asir
> > >
> > > -----Original Message-----
> > > From: w3c-xml-schema-ig-request@w3.org 
> > > [mailto:w3c-xml-schema-ig-request@w3.org]On Behalf Of
> Asir S Vedamuthu
> > > Sent: Wednesday, August 21, 2002 11:17 AM
> > > To: 'w3c-xml-schema-ig'
> > > Subject: Challenges raised by INLINE Schema Definitions
> > >
> > >
> > >
> > > What is an INLINE Schema Definition?
> > >
> > > It is one or more schema elements; is not a root of the element 
> > > tree; embedded within an XML document. Example, a schema element 
> > > as a child of <types> element in a web service description.
> > >
> > > INLINE schema definitions are very popular and raises many 
> > > challenges. Based on the existing usage patterns, this e-mail 
> > > describes three challenges faced by schema processors. This is not

> > > an exhaustive list. There are many more challenges along these 
> > > lines ..
> > >
> > > I request the schema WG and IG members to discuss these issues and

> > > issue erratta, publish a note on inline schema definitions, OR 
> > > address these in XML Schema 1.1 version.
> > >
> > >
> > > [1] What is the relationship among multiple INLINE schema
> definitions?
> > >
> > > Current usage pattern: inline multiple schema definitions as 
> > > children of <types> element in a web service description. There 
> > > are references to schema components across schema definitions 
> > > without using <xsd:include> or <xsd:import>
> statements.
> > >
> > > Example is,
> > >
> > > <wsd:types xmlns:A="http://www.example.com/A"
> > >            xmlns:B="http://www.example.com/B">
> > >
> > >  <xsd:schema targetNamespace="http://www.example.com/A">
> > > <xsd:element name="a" type="xsd:string"/>
> > > ..
> > >  </xsd:schema>
> > >
> > >  <xsd:schema targetNamespace="http://www.example.com/B">
> > >   <xsd:element name="b" type="xsd:int"/>
> > >   ..
> > >  </xsd:schema>
> > >
> > >  <xsd:schema targetNamespace="http://www.example.com/C">
> > >   <xsd:element name="c">
> > >    <xsd:complexType>
> > >     <xsd:sequence>
> > >      <xsd:element ref="A:a"/>
> > >      <xsd:element ref="B:b"/>
> > >     </xsd:sequence>
> > >    </xsd:complexType>
> > >   </xsd:element>
> > >  </xsd:schema>
> > >
> > > </wsd:types>
> > >
> > > What is the relationship? Is this legal? If so, what are the 
> > > processing rules?
> >
> > No it's not legal, because there is no import statement in
> 'C'. However,
> > the following WOULD be legal
> >
> >  <wsd:types xmlns:A="http://www.example.com/A"
> >             xmlns:B="http://www.example.com/B">
> >
> >   <xsd:schema targetNamespace="http://www.example.com/A">
> >   <xsd:element name="a" type="xsd:string"/>
> >   ..
> >   </xsd:schema>
> >
> >   <xsd:schema targetNamespace="http://www.example.com/B">
> >    <xsd:element name="b" type="xsd:int"/>
> >    ..
> >   </xsd:schema>
> >
> >   <xsd:schema targetNamespace="http://www.example.com/C">
> >    <xsd:import namespace='http://www.example.com/A' />
> >    <xsd:import namespace='http://www.example.com/B' />
> >    <xsd:element name="c">
> >     <xsd:complexType>
> >      <xsd:sequence>
> >       <xsd:element ref="A:a"/>
> >       <xsd:element ref="B:b"/>
> >      </xsd:sequence>
> >     </xsd:complexType>
> >    </xsd:element>
> >   </xsd:schema>
> >
> >  </wsd:types>
> >
> >
> >
> > >
> > >
> > > [2] AD HOC Built-in Types and Declarations
> > >
> > > Per XML Schema 1.0, there are a few built-in types: 'anyType' and 
> > > 'anySimpleType' from Part 1 and built-in simple types
> from Part 2.
> > >
> > > Current usage pattern: certain type definitions and element / 
> > > attribute declarations that are germane to web service domain are 
> > > implicitly treated as built-in types and decls. Here is an 
> > > example,
> > >
> > > Example 3, WSDL Version 1.2: Bindings 
> > > http://www.w3.org/TR/2002/WD-wsdl12-bindings-20020709/#_soap-e
> > >
> > > <types>
> > >   <schema targetNamespace="http://example.com/stockquote/schema"
> > >     xmlns="http://www.w3.org/2000/10/XMLSchema">
> > >     ..
> > >     <complexType name="ArrayOfFloat">
> > >      <complexContent>
> > >       <restriction base="soapenc:Array">
> > >         <attribute ref="soapenc:arrayType" 
> > > wsdl:arrayType="xsd:float[]"/>
> > >       </restriction>
> > >      </complexContent>
> > >     </complexType>
> > >   </schema>
> > > </types>
> >
> > This is illegal too. There should be a
> >
> > <xsd:import namespace='http://schemas.xmlsoap.org/soap/encoding/' />
> >
> > >
> > > In this example, complex type soapenc:Array and attribute decl 
> > > soapenc:arrayType are considered to be built-ins. I believe that 
> > > this sample schema definition is invalid per XML Schema 1.0 spec. 
> > > Because, there aren't any import statements for the soapenc 
> > > namespace, http://schemas.xmlsoap.org/soap/encoding/. However, 
> > > this usage pattern demonstrates a need for extensible built-ins.
> >
> > I disagree, I think people should put the import statements into the

> > schemas
> >
> > >
> > > Today, this usage pattern is widely used and enforced by ad hoc 
> > > groups.
> >
> > WSDL 1.2 could ( and should ) fix this.
> >
> > >
> > >
> > > [3] Mandatory targetNamespace
> > >
> > > Per XML Schema 1.0, targetNamespace is optional. If absent, then 
> > > this schema definition defines and declares components that are 
> > > not considered to be in any namespace.
> > >
> > > Current usage pattern: targetNamespace is mandatory for inline 
> > > schema definitions within a web service description.
> >
> > What makes you think this? Given that all that appears in a
> 'wsdl:types'
> > element are <xsd:schema> elements, I don't see how anyone
> can mandate
> > targetNamespace without changing the schema spec. Is this a
> tools issue?
> >
> > >
> > > This takes away a huge functionality. I do know that implementers 
> > > have gone to lengths to implement this restriction. Let me 
> > > describe our experience. There are several webMethods users that 
> > > depend on ABSENT targetNamespace. To overcome this restriction and

> > > support these users, we have introduced a special namespace URI in
> > > markup that represents absent [namespace name] in XML
> > > Information Sets - http://www.webMethods.com/noNamespace/ and
> > > this is the targetNamespace :-( Here is a sample,
> > >
> > > <xsd:schema
> targetNamespace="http://www.webMethods.com/noNamespace/"
> > >  xmlns="http://www.webMethods.com/noNamespace/">
> > >
> > >  <xsd:complexType name="purchaseOrder">
> > >   <xsd:sequence>
> > >    <xsd:element name="shipTo" ..
> > >    ..
> > >   </xsd:sequence>
> > >  </xsd:complexType>
> > >
> > >  <xsd:simpleType name="SKU">
> > >   <xsd:restriction base="xsd:string">
> > >    <xsd:pattern value="\d{3}-[A-Z]{2}"/>
> > >   </xsd:restriction>
> > >  </xsd:simpleType>
> > > </xsd:schema>
> > >
> > > I believe that making targetNamespace mandatory is a huge loss of 
> > > functionality.
> >
> > I'm not sure it's huge, but it is certainly a loss!
> >
> > It is not clear to me why these are issues for the schema
> WG/IG. Surely
> > these are issues for the WSDesc WG, no?
> >
> > Gudge
> 
> 
Received on Sunday, 8 September 2002 20:25:00 GMT

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