32-1:
	conn / as sysdba
	GRANT EXECUTE ON dbms_flashback TO scott;
32-2:
	CREATE OR REPLACE FUNCTION emp_info(time TIMESTAMP) RETURN VARCHAR2 IS
	  info VARCHAR2(3000);
	BEGIN
	  dbms_flashback.enable_at_time(time);
	  FOR emp_record IN
	    (SELECT ename,sal FROM emp WHERE deptno=10) LOOP
	    info:=info||':'||emp_record.ename||',:'||emp_record.sal||chr(10)||chr(13);
	  END LOOP;
	  dbms_flashback.disable;
	  RETURN info;
	END;
	/
	UPDATE emp SET sal=sal+100 WHERE deptno=10;
	COMMIT;
	INSERT INTO emp (empno,ename,sal,deptno) VALUES(1234,'MARY',1200,10);
	COMMIT;
	DELETE emp WHERE empno=1234;
	COMMIT;
	SELECT emp_info(systimestamp) FROM dual;	
	SELECT emp_info(systimestamp-2/24/60) FROM dual;
	SELECT emp_info(systimestamp-4/24/60) FROM dual;

