Re: [xml-dev] What does "optional" mean?

[Alex Muir <alex.g.muir@gmail.com>]

I would disagree that this is an example that makes the notion optional needed.

On Sun, Feb 26, 2012 at 2:51 PM, Mukul Gandhi <gandhi.mukul@gmail.com> wrote:
> Following is an use case, that probably makes the notion of "optional"
> in XML documents *necessary*,
>
> Let's assume, that a book object may be represented in an XML format
> in either of following ways,
>
> <book isbn="123">
>   <name>book1</name>
> </book>
>
> OR
>
> <book>
>   <isbn>123</isbn>
>   <name>book1</name>
> </book>
>
> i.e, an ISBN number of book may be represented either as an attribute
> or as a child element of element book, but not at both of these
> places

This I would think is the kind of thing you wouldn't do. It would be
better to stick to one or the other and perhaps better to use an
element for readability as the number of attributes increase. Don't
forget that an optional choice like this means more programming in
that a case now is required to check which one exists and perhaps an
error check to make sure they don't both exist.

I suppose a privacy element should have optional aspects depending on
how information much you want to give or were able to collect from
someone.

<Privacy>
 <Name>jasmine</Name>
<SSN>2334434</SSN>
...
</Privacy>

-- 


Alex Muir
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