I am testing the Oracle Cloud service. The first question is: if I have some "classical" client-server application, which works with my non-Cloud Oracle database through the "classic" Oracle connect string which has the following view: USER/PASSWORD@192.168.0.10:1521:xe, will be the same application able to work with on-Cloud database remotely (after I move my database on the cloud) through the same connect string? If yes, then what parameters should I use in this connect string from the information letter which I have received as the Account Administrator and the Identity Domain Administrator for the Oracle Cloud service? (the application is written on Delphi and uses known ODAC components for connection to the Oracle database). The second question: can I connect to my test cloud database from SQL*Plus?
You cannot access the Database Cloud with SQL*Net, so no connect string will work, for an app or SQL Plus. You can use either SQL Workshop within Application Express or SQL Developer to do what you would do with SQL*Plus.