Oracle PL/SQL Tutorial/SQL PLUS Session Environment/SYS CONTEXT

Get current program with sys_context("userenv","sessionid") and v$session

SQL>
SQL>
SQL> set serveroutput on
SQL> declare
  2    myModule varchar2(48);
  3  begin
  4    select b.module into myModule from v$session b where b.audsid = sys_context("userenv","sessionid");
  5    dbms_output.put_line("Current Program is " || myModule);
  6  end;
  7  /
Current Program is SQL*Plus
PL/SQL procedure successfully completed.
SQL>
SQL>

sys_context(""userenv"",""sessionid"")

SQL>
SQL>
SQL> create or replace function myFunction
  2  return varchar2
  3  authid current_user
  4  as
  5    myModule varchar2(48);
  6    cmd varchar2(500);
  7  begin
  8     cmd := "select b.module " ||"from v$session b " ||"where b.audsid = sys_context(""userenv"",""sessionid"")";
  9     execute immediate cmd into myModule;
 10     return myModule;
 11  end;
 12  /
Function created.
SQL> select myFunction from dual;
1 row selected.

SQL> drop function myFunction;
Function dropped.
SQL>

Use SYS_CONTEXT to retrieve the database name

SQL> SET TERMOUT OFF
SQL>
SQL> --Specify that new values for the database_name column
SQL> --go into a substitution variable called databasae_name
SQL> COLUMN database_name NEW_VALUE database_name
SQL>
SQL> --. 
SQL> SELECT SYS_CONTEXT("USERENV","DB_NAME") database_name
  2  FROM dual;
User System Privileges                                              Page    1
DATABASE_NAME
-----------------------------------------------------------------------------
XE
1 row selected.
SQL>