ODBC monitoring without DSN was implemented in 5.0.0. It works well with MySQL, PostgreSQL and FreeTDS but doesn't work with Oracle (driver version 19.1, unixODBC 2.3.1). Hovever, it works well in classic way with DSN in odbc.ini.

Connection strings tested:

db.odbc.get[test,,"Driver=Oracle;ServerName=testserver:port/database"]
db.odbc.get[test,,"Driver=Oracle;ServerName=testserver;Port=Port;DSN=database"]

User and password are in macroses.