The Schema Connection Information dialog box contains three fields which enable the complete connection information for an Oracle schema to be specified.
What the fields mean: The Username and Password fields are the Oracle schema username and password and are not case sensitive. The Database field is the Oracle TNSNAMES entry for that database. It is important to realise that this entry is the entry in the PC's tnsnames.ora file not the one listed on the server. It is essential that you ensure the TNSNAMES field is configured accurately so that it connects you to the correct database.
Basically, these three fields are the same as you would use to connect to the database from the PC via the Oracle SQL*Plus application.