问题
How can i define relationship between subclasses in XML, for example a class researcher has two subclass Paper and author .
回答1:
Normally you would be using an XML schema to describe relationships in an XML file. But I seriously doubt you should make a model where researcher has subclass paper and author, it seems more like researcher is related to the class Paper in the role of Author. All of this you can describe in XML Schema.
来源：https://stackoverflow.com/questions/432699/how-to-reflect-relationship-beween-subclasses-in-xml