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Re: Rationale for Dropping the <soap:body use=...> Attribute

From: Ricky Ho <riho@cisco.com>
Date: Wed, 18 Sep 2002 10:49:47 -0700
Message-Id: <>
To: ryman@ca.ibm.com, Jacek Kopecky <jacek@systinet.com>
Cc: WS Description WG <www-ws-desc@w3.org>

Representing "graph" using XML Schema via the ID and IDREF is very very 
limited.  Today, you cannot specify an IDREF that reference a certain 
schema type.  (in other words, the IDREF is typeless so schema validation 
cannot traverse across an IDREF).

This create a challenge for validating messages with SOAP encoding because 
a complex object are typically referenced by an IDREF.  In other words, the 
SOAP message format (using SOAP encoding) on the wire is not compliant with 
what is defined in the WSDL.

Best regards,

At 09:59 AM 9/18/2002 -0400, ryman@ca.ibm.com wrote:

>I agree that the original authors of the WSDL had a lot of generality in
>mind concerning multiple type systems. However, I prefer the viewpoint that
>messages should be described abstractly, so all you really need is one
>sufficiently expressive type system. XML Schema fills that role. While it
>is best for tree-like data, it can also be used for graphs via the ID and
>IDREF types.
>All details about how the message is formatted should be in the binding.
>For the SOAP binding, we are proposing that the only binding we need is
>literal. Attempts to use a more flexible bindings, SOAP encoding, led to
>interop problems.
>So, no, I'd say not to use a different kind of schema language. Leave the
>message definition independent of the binding. If more flexibility is
>really needed, then modify the SOAP binding rules, but specify the encoding
>algorithm more clearly to eliminate interop problems.
>Arthur Ryman
>                       Jacek 
> Kopecky 
>                       <jacek@systinet.c        To:       Arthur 
> Ryman/Toronto/IBM@IBMCA 
>                       om>                      cc:       WS Description 
> WG <www-ws-desc@w3.org>
>                                                Subject:  Re: Rationale 
> for Dropping the <soap:body use=...> Attribute
>                       09/18/2002 
> 07:39 
>                       AM 
>  Arthur, others,
>  I agree that use="literal" should be sufficient in WSDL. My
>understanding has always been that for other datamodel than the XML Tree
>datamodel of XML Schema, other schema languages should be used in WSDL
>descriptions - something like
><soapenc:schema targetNamespace="foo" xmlns="foo" xmlns:foo="foo">
>   <soapenc:struct name="myStruct">
>      <soapenc:edge name="a" targetType="myStruct"/>
>      <soapenc:edge name="b" targetType="myArray"/>
>      <soapenc:edge name="c" targetType="soapenc:simple"/>
>   </soapenc:struct>
>   <soapenc:array name="myArray" dimensions="3">
>      <soapenc:edge targetType="soapenc:simple"/>
>   </soapenc:array>
>and then a message part of type foo:myStruct would be literally
>serialized according to its schema, whichever variant of the actual XML
>instance is the result.
>  Is this how others see the issue, too? 8-)
>  Best regards,
>                    Jacek Kopecky
>                    Senior Architect, Systinet Corporation
>                    http://www.systinet.com/
Received on Wednesday, 18 September 2002 13:50:40 UTC

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