PLSQL 触发器为每行设置 new.列不起作用

Question

>当我插入所有主题值时，我正在尝试计算表中的总值。这是我的plsql代码：

CREATE OR REPLACE TRIGGER stud_marks before INSERT OR UPDATE ON student_report 
FOR EACH ROW 
BEGIN
set new.total := :new.sub1 + :new.sub2 + :new.sub3;
END;

这是我得到的错误：

 Warning: Trigger created with compilation errors.
 SQL> show error; Errors for TRIGGER STUD_MARKS:
 LINE/COL ERROR
 -------- ----------------------------------------------------------------- 
 2/1      PL/SQL: SQL Statement ignored 2/5      PL/SQL: ORA-00922: missing or invalid option

Answer 1

应该是

CREATE OR REPLACE TRIGGER stud_marks before INSERT OR UPDATE ON student_report 
FOR EACH ROW 
BEGIN
:new.total := :new.sub1 + :new.sub2 + :new.sub3;
END;
before insert ( :new=new inserted value :old=null);
before update ( :new=new updated value :old=old value);