I am looking for a testing database that contains random tables full of random data where I can do my test. I just began studying Oracle express edition 11g, I am using Oracle SQL developer under Windows 7. I would like to have database's entity relation ship diagram so it would be easy for me to know table's attributes key...
Based on this stackexchange question, I found the page:
Also, if you are using XE, there is a demo DB ready to play with.