I know this is not necessarily a good idea for performance reasons, both in loading and querying, but ... is it possible to automatically translate DTD descriptions into SQL DDL and corresponding code to parse the XML and load the data?

How do you know (or what makes you think) that parsing a DTD is "not ... a good idea for performance reasons ..."? I doubt that using this sort of facility would have any noticeable impact on run-time performance, and it could certainly be a major boost to programmer performance (and would a good way to reduce code that is too bulky and ad-hoc).

You're right; I don't know for sure, and I agree about the savings in programmer time (frankly what I was interested in). The medline database has 15,000,000 big fat records, and I was guessing that a hand-teaked, denormalized table layout would be more optimal for querying and maybe data loading. But I don't know yet. Thanks for pointing out the CPAN modules. I was just wondering if I had overlooked a module that does exactly what I am interested in.