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Re: Derivation by restriction

From: by way of Michael McLay <mclay@nist.gov>
Date: Tue, 8 May 2001 03:31:55 -0400
To: xmlschema-dev@w3.org
Message-Id: <01050803315509.02044@fermi.eeel.nist.gov>

On Tuesday 08 May 2001 03:41, Henry S. Thompson wrote:
> Eddie Robertsson <eddie@allette.com.au> writes:
> > In the section for restriction in the Primer (4.4) it reads (last
> > sentence before the example):
> >
> > "Notice that types derived by restriction must repeat all the components
> > of the base type definition that are to be included in the derived
> > type:"
> >
> > However, I don't believe this is true for attributes.
>
> You're right.  The sentence above needs to be understood as
> "components _of the content model_".

In section 4.4 of the primer the example titled "Deriving ConfirmedItems by
Restriction from Items" includes the definition of an attribute "PartNum".
Could this been left out of the definition of the restricted definition?

Why is it that the components of the context model must be repeated and how
much must be repeated?  For instance, if a restriction is done on an 
ComplexType that is defined as an extension of a ComplexType what must be 
redeclared when defining the restriction?

I also noticed in this example that the type for "USPrice" in the example in 
section 4.4 does not match the definition defined in 2.1 "The Purchase Order 
Schema, po.xsd" 

In 4.4 the element definition is: 

   <element name="USPrice"    type="decimal"/>

and in 2.1 the element definition is:

   <xsd:element name="USPrice"  type="xsd:decimal"/>

The xsd prefix isn't used in the one, but it is in the other.  
Received on Tuesday, 8 May 2001 16:31:42 GMT

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