Tools to generate a database diagram/ER diagram from existing Oracle database? [closed]

Try out Oracle SQL Developer. It is from oracle and is going to be part of actual oracle installation from 11g onwards. It has a separate build modeler tool to engineer or re-engineer an ER model.

Other tool that may be useful that will help you more than just genereate ER diagram is SchemaSpy

SQL Developer is awesome. Supports all the databases and perfect for reverse engineering. It free and Java.

Its Free unlike other solutions listed above and it works, I just used it to reverse engineer a Postgres db!!!

I few years ago, I used Data Architect, part of Power Designer from Sybase. It's a little pricy, but it's excellent. And it makes a fine distinction between the physical (SQL) model of data and the ER model of data. It keeps both models side by side.

If you are not too concerned about the difference between SQL and ER, and you just want a diagram, here's something I did once when I needed a diagram in a big hurry.

Crank up MS Access with a new empty database. Set up table links to all the tables in the schema, or just the ones you want to diagram. Use the "Relationships" tool in Access to create lines between the foreign keys and the primary keys they refer to. Classify these relationships as to many-to-many or many-to-one.

In the Access relationships view, move the boxes around until the diagram is pretty. Print.