MY.CHANGED_BY := USER;
 MY.CHANGED_TIME := SYSDATE;

 SELECT TERMINAL FROM SYS.AUD$ 

 MY.CHANGED_BY := USER;
 MY.CHANGED_TIME := SYSDATE;

 SELECT TERMINAL FROM SYS.AUD$ 

CREATE TABLE DEPT$AUDIT (
        DEPTNO       NUMBER,
        DNAME        VARCHAR2(14 byte),
        LOC          VARCHAR2(13 byte),
        CHANGE_TYPE  VARCHAR2(1 byte),
        CHANGED_BY   VARCHAR2(30 byte),
        TERMINAL        VARCHAR2(50),
        CHANGED_TIME DATE
    );
    
    SELECT * FROM DEPT$AUDIT;
    
    
    CREATE OR REPLACE TRIGGER AUDITDEPTAR AFTER
    INSERT OR UPDATE OR DELETE ON DEPT FOR EACH ROW
    DECLARE
    MY DEPT$AUDIT%ROWTYPE;
    BEGIN
        IF INSERTING THEN MY.CHANGE_TYPE := 'I';
        ELSIF UPDATING THEN MY.CHANGE_TYPE :='U';
        ELSE MY.CHANGE_TYPE := 'D';
        END IF;
 
       MY.CHANGED_BY := USER;
       MY.CHANGED_TIME := SYSDATE;
       MY.TERMINAL := SYS_CONTEXT/USERENV;

       CASE MY.CHANGE_TYPE
       WHEN 'I' THEN
          MY.DEPTNO := :NEW.DEPTNO;
         MY.DNAME := :NEW.DNAME;
         MY.LOC := :NEW.LOC;
      ELSE
         MY.DEPTNO := :OLD.DEPTNO;
         MY.DNAME := :OLD.DNAME;
         MY.LOC := :OLD.LOC;
      END CASE;
 
      INSERT INTO DEPT$AUDIT VALUES MY;
  END;

 [Error] PLS-00306 (29: 23): PLS-00306: wrong number or types of arguments in call to 'SYS_CONTEXT'

select SYS_CONTEXT('USERENV', 'IP_ADDRESS') from DUAL;