An application created with 4GL or one of the embedded query languages can use its own set of key mappings, invoked by the set_frs frs or set_forms frs (for 4GL) statements. Applications developers can use these statements in an application to read in a key‑mapping file that is specific to that application or to map a FRS key to a function or control key explicitly in the application code.

An application mapping file takes precedence over the FRS mapping file. When an application starts up, the FRS merges all mapping files and resolves any conflicts between mapping statements by giving precedence to the statement in the mapping file of highest precedence. The FRS always honors the most recent reference to any mappable key in the file with the higher level of precedence.

For more information on application key mapping, see the Forms-based Application Development Tools User Guide.