Mapping and conversion between tables that have different data structures requires either a source-definitions file, a target-definitions file, or in some cases both. Mapping between dissimilar databases is controlled by the self-describing trails, and mapping is done by column name, regardless of the data type for the source or target column.

If you don't want automatic mapping based on the self-describing trails or want backward compatibility then you can use SOURCEDEFS or TARGETDEFS.