While working on the import process to bring the XML data into the website database, it occurred to me that, after all of the changes to the schema, the <case> element doesn't serve much of a function anymore. While it used to group together multiple trial files, all of the useful grouping information (namely the trial dates) has been moved to the <trial_file> elements themselves. So, we don't need the extra level in the hierarchy.
For that matter, we also don't need the <regular_cases> element that wraps up the <case> elements, since it's also an extra level of hierarchy. The schema really just needs to be: data -> one or more trial files
Thus, I've removed <regular_cases> <case> from the schema and modified the XSLT transformation scripts accordingly. I also modified the data that's already been processed.
These changes will make the PHP script that converts the XML to MySQL simpler.