Documentation

I'd like to know what best practice is on documenting a new database that I
created. What type of diagrams and definitions and how specific or high
level should the documentation be?
Thanks
that's hard to answer without knowing the particulars of your database
or application, however, i use the following guideline for documenting
pretty much anything i work on: if someone new were to take over your
role, would they have enough documentation to do the job?
sorry for the unspecific answer.
arthur