SQL & PL/SQL

I need to document my database objects with respect to:
What objects I have , relationship with in tables , keys in tables Etc…
This document should be good enough to explain the business flow (data flow) in DB

What I am looking is :: A good template or approach any idea or suggestion.

--ER diagrams is 1 thing in my mind any other thing anyone what to suggest
--Coding standard is something different


thanks in advance;