How to connect an Oracle Database to Mathematica?

I am trying to connect an Oracle database to Mathematica 8. Another question already says how it can be done in for a MySQL database but it does not work for me:

Needs["DatabaseLink"] AND conn = OpenSQLConnection[JDBC["MySQL(Connector/J)", 
"yourserver/yourdatabase"], "Username" -> "yourusername", "Password" -> "yourpassword"]

The following information is available for me on my desktop:

filepath = "C:\oracle\ora92\network\ADMIN\tnsnames.ora"; HOST; PORT; username; password;

conn = OpenSQLConnection[JDBC["MySQL(Connector/J)", HOST], "Username" -> username, "Password" -> password]

Error message: JDBC::error: 
    Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. 
    The driver has not received any packets from the server. >>

Does anyone know how I can connect or continue?