How to make a good documentation of a database ?

Hi !

I've just inherited the responsibility of a postgresql database
of roughly 480 tables and 6460 columns, mainly without constraints,
not even foreign keys.

I'd like to make it a little more orthodox (lots and lots of
constraints, yeah !!), but I need a tool to make a documentation about
every column, at least, as some column are really vicious (like, they
are a foreign key to a table which depends on the type of another column...).

The best idea I could come with to do that was to maintain an output of
pgdump --shema-only, versioned with cvs, annotated with a patch, itself
versioned with cvs.
Not that bright, isn't it ?

The problem is, I don't want to use a lot of time to maintain this
documentation, and above all, I'd prefer not to insert the information
twice (read: a new constraint in the database should automagically
update the documentation).

Does somebody know the right way to do this ?

Best regards,
David Pradier

--
dpradier@apartia.fr - tel: 01.46.47.21.33 - fax: 01.45.20.17.98