DTD - Element Hierarchy?

[mcfly1204]

Is it possible to declare an element hierarchy in a DTD? For instance, if two elements hold the same information, but one is supposed to supersede the other, can that be defined in a DTD? If not, where could that hierarchy be defined?

[rski]

Please post an example.

[mcfly1204]

I do not see how an example would help answer this question. Is there a way to define a hierarchy of elements where if one element is populated, that information supersedes the information of another element.

[Dormilich]

a DTD is supposed to define the order of elements in the SGML document and their (static) properties. though you can define default values, dynamic behaviour is not the realm of DTD.

[mcfly1204]

That is how I understood the purpose of DTDs as well. Thanks for the confirmation.