Understanding XML Schemas
by Norman Walsh | Pages: 1, 2, 3, 4, 5, 6, 7

Conclusion

Looking at the scope and functionality that schemas will provide, they seem like a great improvement over DTDs. Certain kinds of applications, exchanging information between databases, for example, and ecommerce are clearly going to be made simpler and more interoperable by XML Schema.

As I see it, the primary virtue of DTDs today is that they are well understood and they do offer a good way to describe the structure of an document for interchange. It will take some time before XML Schema are as well understood. Until then, we'll be "flying without a net" to a certain extent, waiting for the final standard and practical, documented methodologies for schema creation to follow.