CREATE OR REPLACE PACKAGE my_security_pkg 
AS 
   FUNCTION hash_value( 
      p_input_string_in IN VARCHAR2 
      ) 
   RETURN VARCHAR2 DETERMINISTIC; 
END my_security_pkg; 

CREATE OR REPLACE PACKAGE BODY my_security_pkg 
AS 
   FUNCTION hash_value( 
      p_input_string_in IN VARCHAR2 
      ) 
   RETURN VARCHAR2 DETERMINISTIC 
   IS 
   BEGIN 
      RETURN DBMS_CRYPTO.HASH(UTL_I18N.string_to_raw(p_input_string_in),DBMS_CRYPTO.hash_sh512); 
   END hash_value; 
END my_security_pkg; 

DROP TABLE my_emp

CREATE TABLE my_emp 
AS( SELECT * FROM SCOTT.emp ) 

ALTER TABLE my_emp 
ADD hashkey      VARCHAR2(512) 
GENERATED ALWAYS AS( 
   CAST(MY_SECURITY_PKG.hash_value(TO_CHAR(empno) || '|' || ename || '|' || job || '|' || TO_CHAR(mgr) || '|' || TO_CHAR(hiredate, 'mm/dd/yyyy') || '|' || TO_CHAR(sal) || '|' || TO_CHAR(comm) || '|' || TO_CHAR(deptno)) 
   AS VARCHAR2(512)) 
   )