Optional attributegroup?

[Nik]

Hello,

I'm writing a validation schema for some XML and I wonder if there is
a good way to validate the following scenario:

The element:

<foo bar.1="1" bar.2="2" bar.4="4" tar="3"/>

The entire element is optional but that can be handled with
min/maxoccurs. The problem is the bar.* attributes. How can I define
that e.g. bar.[1-4] are optional but if any one of them are present
then the others should be present too?

Thanks in advance

 

[Martin Honnen]

Nik wrote:

I'm writing a validation schema for some XML and I wonder if there is
a good way to validate the following scenario:

The element:

<foo bar.1="1" bar.2="2" bar.4="4" tar="3"/>

The entire element is optional but that can be handled with
min/maxoccurs. The problem is the bar.* attributes. How can I define
that e.g. bar.[1-4] are optional but if any one of them are present
then the others should be present too?

In my view neither a DTD nor a W3C XML schema allows you to model such a
constraints involving different attributes.