Hi Xiaofeng,

See http://www.w3.org/TR/xmlschema-1/#element-complexContent..extension
The content type of the extended type whose base content type and 
effective content are not empty is a sequence containing the base 
content type and the effective content.

So you will get as a result for the extended type a content type 
particle of the form:

xs:sequence (
	baseContentTypeParticles
	effectiveContentParticles
)

As xs:all cannot appear inside xs:sequence it means that you should not 
use it in neither the base nor in the extended type.

Best Regards,
George
---------------------------------------------------------------------
George Cristian Bina
<oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
www.---.com


Xiaofeng Wang wrote:
> Hi All,
> 
> I can define a complexType A with a set of elements
> using xs:all, xs:sequence, or xs:choice. I understand
> the difference between them. What confuses me is that
> if I want to define a new complexType B which extends
> complexType A using xs:extension, will xs:all,
> xs:sequence, and xs:choice have different impact on
> the extension?
> 
> Thanks a lot
> Xiaofeng
> 
> 
> 
> 
> 		
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From mike@s... Fri May 13 08:36:14 2005
Received: from lisa.w3.org ([128.3