Oracle Database Discussions

HI,

I am working on SQL Developer tool without installing oracle into my local machine.
I just took server IP as hostname and continuing with the same/

Now, since I donot have tns names, I am not able to use any other user other than my work related.
like scott etc.

could anyone let me know, is there any way that i can work on sql developer or pl/sql developer without installing oracle into local machine

like using scott etc...
for testing and learning purpose of self code.

thanks in advance.