Copying the data out to a reporting database might be easier depending on what you're trying to accomplish. The data structure for Forms is somewhat complicated because it has to support an infinite number of variations in form fields.

The secondary concern would be that the underlying database is subject to change when new versions are released and that could break your reports. If you use workflow to retrieve field values and put them into a secondary database you could structure the data exactly the way you want.

If you want to pursue reporting directly off the Forms database, it is going to require joins on several tables to get the form, instances, submissions, variables, etc. Basically there's no single database entry for a form/submission, it is a complex web of relationship mapping.