SQL Developer Connection

I am trying to connect to a开发者_C百科 database in SQL Developer so I can start practising SQL. Which db should I create a connection with to begin is it 10g express?

I have tried creating a new connection; however, I have not been successful. I keep getting the error message:

"Status : Failure-Test failed: IO Error: The Network Adapter could not establish the connection"

I am really lost, all the tutorials I can find seem to move through the new connection process effortlessly without any connection error help; most of the information seems to be more advanced than the basic setup help I need.

Thanks.

PS. any good beginner resources for learning SQL would be much appreciated.

http://connectionstrings.com

And the oracle page there:

http://connectionstrings.com/oracle

It doesn't look like Oracle has any online development database that you can connect to, so it seems like your best bet is to run express edition locally and use some of the sample schemas. More info here: http://www.oracle.com/technetwork/developer-tools/sql-developer/getting-started-155046.html