创建触发器时出错（SQL开发人员3.2）

Question

我似乎无法找到此错误的原因，大多数示例iv检查使用此方法但我的SQL编译器似乎有/ END语句的问题。

我的触发器

CREATE OR REPLACE 
TRIGGER STUDENTS_ID_TRIG 
BEFORE INSERT ON STUDENTS
REFERENCING NEW AS NEW
FOR EACH ROW
BEGIN
  if(:new.STUDENT_ID = null) then
  SELECT STUDENTS_ID_SEQ.nextval
  INTO :new.STUDENT_ID
  FROM dual;
  end if;
END;
/
ALTER TRIGGER "STUDENT_ID_TRIG" ENABLE

我的序列

CREATE SEQUENCE  "APEX90"."STUDENT_ID_SEQ"  MINVALUE 1 MAXVALUE 99999 INCREMENT BY 1 START WITH                     11 CACHE 10 NOORDER  NOCYCLE  NOPARTITION ;

错误

Trigger APEX90.STUDENTS_ID_TRIG@APEX90
Error(13,1): PLS-00103: Encountered the symbol "/"