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   Re: [xml-dev] Where have the element types gone?

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Eric van der Vlist wrote:
> Now, if instead of this I define in a schema a "isbn" element in my
> own namespace (or lack of namespace) having the datatype "pub:isbn":
> <xs:element name="isbn" type="pub:isbn"/>
> my instance document is:
> <book>
>    <isbn>....</isbn>
> ...
> </book>
> and determining that the content of <isbn> is a isbn number as defined
> by the namespace prefixed as "pub" requires to process the schema.

Not true.

1) Before we had namespaces, you made an assumption about the data type
of the element based on its name, which might not have been universal.

2) After we had namespaces, and you chose to use them, you made an
assumption about the data type of the element based on its name, which
was "guaranteed" to be universal.

3) After we had schemas (and simple and complex types), you can still do
(1) -- which is what you have done here -- or (2). You also have the
additional ability to query the data type at run time if the schema is

Each step gives you more options, but doesn't take away any of the
previous options.

BTW, in my opinion (this really isn't meant to be flame bait, but I
suppose it will be anyway), defining element types without using
namespaces is a bad idea for the long term. Your XML might be isolated
now, but there is no guarantee that you or somebody unknown to you might
want to reuse your XML at some point in the future, making universal
names a very useful thing.

-- Ron


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