Optionally, create a decision making function if you want to use the MATCH_FUNCTION and MATCH_FUNCTION_PARAMS symbols.
You can define additional symbols in the DefMaskRSSym security rule that use a PL/SQL function to determine whether to mask the stored procedure. If you want to use the MATCH_FUNCTION and MATCH_FUNCTION_PARAMS symbols, you must create a PL/SQL function that returns 0 or 1. If the function returns 1, Dynamic Data Masking masks the stored procedure. If the function returns 0, Dynamic Data Masking does not mask the stored procedure.