To connect to Oracle with exMon you need to install ODAC on the exMon machine.
1. It is helpful to start with setting up SQL Developer from Oracle. Google for it to make sure you are receiving the latest version.
You will need an Oracle.com account to download but that is free
2. Download ODAC from Oracle.
When setting up, make sure you select .Net support and to add "System wide support for ASP.NET". That ensures that the Oracle OLE DB driver is added to the GAC.
Also use the installer to set up the first Oracle DB into TNSNames
3. Restart exMon Administrator
4. Add a data provider as usual and set the DB type to Oracle
The connection string should be on the form:
DataSource=CONNECTION NAME;User ID=exmon_reader;Password=%Password%;Persist SecurityInfo=True;Provider=OraOLEDB.Oracle.1;
Note that to make sure the data provider is set up correctly you can create a new query and execute: SELECT sysdate FROM dual