创建触发器时发生Oracle错误

This is my SQL code:

这是我的SQL代码:

CREATE OR REPLACE TRIGGER Promjenaplacanja
BEFORE UPDATE
ON Placanje
FOR EACH ROW
DECLARE
v_PlacanjeID NUMBER(10,0);
v_Starinacin NVARCHAR2(50);
v_Novinacin NVARCHAR2(50);

BEGIN

BEGIN
  SELECT :OLD.PlacanjeID ,
         :OLD.Nacin_Placanja 

    INTO v_PlacanjeID,
         v_Starinacin
    FROM DUAL ;
  SELECT :NEW.Nacin_Placanja 

    INTO v_Novinacin
    FROM DUAL ;
  INSERT INTO Auditplacanja
    ( PlacanjeID, Starinacin, Novinacin, Datum )
    VALUES ( v_PlacanjeID, v_Starinacin, v_Novinacin, SYSDATE ); 
END;
END;
CREATE OR R