Decipher database schema [closed]
Try SchemaSpy. I ran it against a rather complex database and I was quite pleased by the result, with advice on optimization.
Try DBVis - download at http://www.minq.se/products/dbvis/ - there is a pro version (not needed) and a open version that should suffice.
All you have to do is to get the right JDBC - database driver, the tool shows tables and references orthogonal, hirarchical, in a circle ;-) etc. just by pressing one single button. Enjoy!
What DBMS (Database Management System) are you using? Many modern DBMS's like SQL server and Access can create an E-R diagram for you.
Microsoft Visio is an excellent tool and can reverse engineer SQL from any datasource.
DDT (Database Design Tool) can reverse engineer from raw SQL on windows and is very lightweight (very small free download).
MySQL Workbench is one of the more popular MySQL tools and has a freely downloadable version.
SQLFairy can do the same for MySQL on Linux.