Interesting example. As I read MSDN, only the name of a complexType is 
allowed.

(Excerpt)

restriction (complexContent)

base
The name of a complexType element defined in this schema (or another schema 
indicated by the specified namespace). The element containing the 
restriction element is derived from the type specified by the base value.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xmlsdk/html/xsdrefrestrictioncomplexContentElement.asp

Do you happened to have a link of the example?

"Mahalax" <Mahalax@d...> wrote in message 
news:796D6E29-A336-48B7-92B9-CA8C6F73F8CD@m......
> Yes, it does. Here is the MSDN sample.
>
> <xs:attributeGroup name="A">
>  <xs:attribute name="x" type="xs:NCName"/>
>  <xs:attribute name="y" type="xs:QName"/>
> </xs:attributeGroup>
>
> <xs:complexType name="B">
>  <xs:complexContent>
>   <xs:restriction base="xs:A">
>    <xs:attribute name="x" use="required" />
>    <xs:attribute name="y" use="prohibited"/>
>   </xs:restriction>
>  </xs:complexContent>
> </xs:complexType>
>
> -Maha
>
> "Han" wrote:
>
>> I mean reuse. I mean @use attribute at reused attributeGroup.
>> By the way, does MSDN example use name of an attributeGroup for its @base
>> attribute?
>>
>> "Mahalax" <Mahalax@d...> wrote in message
>> news:CE54F817-01C7-487C-B277-F8245F2E0531@m......
>> > Hi Han,
>> >
>> > Actually I am trying to explore the attributegroup and its purpose. 
>> > Many
>> > of
>> > my schemas have a set of common atributes which I am trying to declare
>> > commonly and reuse as required. The code I have posted is an adaptation
>> > from
>> > MSDN which is not working.
>> >
>> > "Han" wrote:
>> >
>> >> OOPS, I mean @use by @required in the earlier post. Values are,
>> >>
>> >> optional, prohibited, required
>> >>
>> >> "Mahalax" <Mahalax@d...> wrote in message
>> >> news:207B477E-4686-4015-8CFE-A510B3AEBE6B@m......
>> >> > Greetings.
>> >> >
>> >> > Below is the schema snippet I am trying to explore attributegroups 
>> >> > and
>> >> > attribute's use property. However I am getting a validation error
>> >> > saying
>> >> > "undefined value for base encountered", pointing to 
>> >> > <xs:restriction>.
>> >> > Please
>> >> > help.
>> >> >
>> >> > <?xml version="1.0" encoding="UTF-8"?>
>> >> > <xs:schema elementFormDefault="qualified"
>> >> > attributeFormDefault="unqualified"
>> >> > xmlns:xs="http://www.w3.org/2001/XMLSchema">
>> >> > <xs:attributeGroup name="grp">
>> >> > <xs:attribute name="x" type="xs:string"/>
>> >> > <xs:attribute name="y" type="xs:string"/>
>> >> > <xs:attribute name="z" type="xs:string"/>
>> >> > </xs:attributeGroup>
>> >> > <xs:complexType name="A">
>> >> > <xs:complexContent>
>> >> > <xs:restriction base="xs:grp">
>> >> > <xs:attribute name="x" use="required"/>
>> >> > <xs:attribute name="y" use="prohibited"/>
>> >> > <xs:attribute name="z" use="required"/>
>> >> > </xs:restriction>
>> >> > </xs:complexContent>
>> >> > </xs:complexType>
>> >> > </xs:schema>
>> >> >
>> >> > Best Regards,
>> >> > Mahalakshmi Natarajan
>> >> > http://mahalax.blogspot.com
>> >> > http://dotnetjunkies.com/weblog/mahalax
>> >>
>> >>
>>
>>