[opencms-dev] xsd:choice in XML Schema or similar functionality in OpenCms

[Dorothee Wiethoff]

Hello list,

I want to define a link element which contains an external link href OR an
internal link href.
It should not to have both elements, but only one of them.
In XML Schema there is the possibility to define an xsd:choice, but this
doesn't work in OpenCms - I got an error message.
Is there another functionality to prohibit the existence of both elements,
e.g. validation rules?
How must this validation rule be defined?

Best regards and thanks in advance,
Dorothee Wiethoff