I think drupal should learn some database normalization rules
Here is the diagram for it , is an pretty complex cms system and that is an bad thing from the kiss philosophy perspective .
I wonder if it can be used for firebirdsql[.ro .org] with an firebird backend now that pdo is used in drupal

http://www.garfieldtech.com/blog/drupal7-database-update
http://drupal.org/node/225450