How to specify in an XML schema that either one of two fields must be present?

Question

I want to specify that either fieldname or freetext must always be present in XML files that apply to this XSD. Is there a way to do that?

Answer 1

There is a Choice Indicator in XML Schema, which allows you to take one of the contained elements, but not two or more. If you want any 2 of 3, I suggest doing something like this:

(Maybe maxOccurs will prevent you from choosing one and the same element twice.) If that does not work, nothing will I think.

Edited: I didn't correctly understand the question the first time. If you want dbtablename to always be present with any one of fieldname or freetext, then this is the answer: