DbSchema is a really cool tool which provides powerful functionalities for visualizing, browsing and running queries. It is free and can be downloaded from http://www.dbschema.com/download.html. Unfortunately, it is not free.

Installing DbSchema on Linux

$ wget http://www.dbschema.com/dbschema.zip
$ unzip dbschema.zip
$ cd DbSchema
$ chmod +x dbschema.sh

To run DbSchema

$ ./dbschema.sh