Here are the tables that comprise the PHP-Nuke database and what they serve for (FIXME: these are still from a very old version! Update! Data model!):
Defines various users profiles.
Defines the administrators and their access levels.
Manages automatic news.
Manages banned users (those excluded from viewing the site).
Manages banner campaigns, impressions and clicks.
Manages the banner campaign clients.
Manages the BBCode.
List of created blocks.
List of the categories.
Manages comments and answers.
Manages some configurations like the possibility to mail in HTML etc.
Manages statistics.
Blocks a user.
Manages categories and subcategories for the download area.
Manages the files present in the download area.
Manages the comments on the files.
Manages the reporting of broken links.
Manages the insertion of files from third parties.
Manages voting on files.
Lists the various encyclopedias.
Lists encyclopedia entries.
Manages recurrent events.
Archives the FAQ answers.
Manages the categories in which the FAQ are subdivided.
Records the last access of the users.
Defines moderators of the forums.
Defines the active forums.
Defines forum topics.
Defines the sources from which to take news with the blocks.
Defines the categories in which the links are subdivided.
Manages the judgments on the links.
Archives the links.
Archives the messages related to the link (broken link etc.).
Archives links suggested for insertion.
Archives link votes.
Defines which is the main module that must be included in index.php.
Manages the home page messages.
Lists and manages the installed modules.
List of the IP addresses that have voted in last 24 hours.
List of survey answers.
List of present and past surveys.
Comment to the survey.
Main titles of forum posts
Manages the module private messages.
Lists the texts waiting for publication
Registers the votes for the news
Lists where the last x rows come from
Associates eventual links to the topics.
Comments to the reviews.
main table of the reviews.
Lists the section texts.
Lists the active sections.
Lists the active sessions.
Lists the supported emoticons.
Statistics module.
Statistics module...
Statistics module.
Statistics module.
Texts of the news.
Categories of the news.
List of topics.
List of users.
Words to censure.