Hi,
For FDM we use the map of the type SDM and for subset we choose the DB accordingly in Datamaker screen. There is no utility to convert one type of map to another that I know of, the function signatures are different for each database type.
It might be a good candidate for an enhancement request.
How to Submit an Enhancement Request for Test Data - CA Knowledge
In the meantime, you would have to create a new map of type Oracle, you cannot use the SDM map for Oracle scripts.
Regards,
Aditi