Since version 3.80 ODAC GUI part is standalone. This means that to make GUI elements such as SQL cursors, connect form, connect dialog etc. available, you should explicitly include OdacVcl unit in your application. This feature is needed for writing console applications.
By default ODAC does not require Forms, Controls and other GUI related units. Only TConnectDialog, TOraErrorHandler and TOraAlerter components require the Forms unit.