As of Drupal 4.6.3 and HEAD today,
uses a fairly simple and optimized set of five tables. This
UML diagram shows how they are logically related together.
2005-11-28 - Update : this page, as well as other in the Grokking Drupal series of my blog, is now available on drupal.org. The version on drupal.org will probably be updated with time, whereas this one probably won't be.