Facing error while trying to create a function using 'ACCESSIBLE BY' clause in PL/SQL Hi everyone hope you're doing well
I'm new to oracle PL/SQL and I'm trying to write a function using 'ACCESSIBLE BY' clause but I receive errors .
this is my function 

create or replace function Show_Description 
(i_Course_Number course.course_no%Type) Return Varchar2
  ACCESSIBLE BY(function show_binary)

   AS

     V_Description Varchar2(50);
  Begin
      Select description
      into V_Description
      from course
      Where course_no = i_Course_Number;
   Return V_Description;

  Exception

   When No_Data_Found Then
     Return('Course Is not in the database');
   When Others Then
     Return('Error in running Show_Description Function');

END; 


I want to know if it's even possible to use 'ACCESSIBLE BY' clause with a function.this the error I receive : ORA-00922 :missing or invalid option
ACCESSIBLE BY is a 12c feature. Based on your previous questions, you have a 11g database.