Re: constraints on attributes as a validation check (ish)

Hi Andy,

Andy Harris <andy.harris@ukbiobank.ac.uk> writes:

> <root>
>     <row typ="g01">
>         <r>content1a</r>
>         <r>content1b</r>
>     </row>
>     <row typ="g02">
>         <r>content2a</r>
>         <r>content2b</r>
>     </row>
>     <row typ="g03">
>         <r>content3a</r>
>         <r>content3b</r>
>     </row>
>     <row type="g05">
>         <r>content4a</r>
>         <r>content4b</r>
>         <r>content4c</r>
>     </row>
> </root>
>
> I need to verify that each file contains one and one only row element of
> type="g04".

This is called co-occurrence constraint and is not supported in the
current revision of XML Schema. Unless you can implement this check
in your application, your best bet is to use element names to carry
type information, e.g.:

<root>
  <row-g05>
    ...
  </row-g05>
</root>

Then you can use the standard XML Schema techniques to restrict the
number of occurrences of this element.

Boris

-- 
Boris Kolpackov
Code Synthesis Tools CC
http://www.codesynthesis.com
Open-Source, Cross-Platform C++ XML Data Binding