正如 Oracle 所说：列列表对于此触发器类型无效。省略它。

示例表和触发器：

SQL> create table bb_basketitem (idproduct number,quantity number);

Table created.

SQL> create or replace trigger user_defined_error
  2    before insert on bb_basketitem
  3    for each row
  4  begin
  5    if    (:new.idproduct = 3 or :new.idproduct = 9)
  6       and :new.quantity < 10
  7    then
  8       raise_application_error(-20000,'Please enter quantity greater than 10.');
  9    end if;
 10  end;
 11  /

Trigger created.

测试：

SQL> insert into bb_basketitem(idproduct,quantity) values (3,5);
insert into bb_basketitem(idproduct,5)
            *
ERROR at line 1:
ORA-20000: Please enter quantity greater than 10.
ORA-06512: at "SCOTT.USER_DEFINED_ERROR",line 5
ORA-04088: error during execution of trigger 'SCOTT.USER_DEFINED_ERROR'


SQL> insert into bb_basketitem(idproduct,20);

1 row created.

SQL>

列列表对 before update 触发器有意义：

SQL> create or replace trigger trg_bu_bbb
  2    before update of quantity on bb_basketitem
  3    for each row
  4  begin
  5    if    (:new.idproduct = 3 or :new.idproduct = 9)
  6       and :new.quantity < 10
  7    then
  8       raise_application_error(-20001,'Please enter quantity greater than 10.');
  9    end if;
 10  end;
 11  /

Trigger created.

SQL> update bb_basketitem set quantity = 1;
update bb_basketitem set quantity = 1
       *
ERROR at line 1:
ORA-20001: Please enter quantity greater than 10.
ORA-06512: at "SCOTT.TRG_BU_BBB",line 5
ORA-04088: error during execution of trigger 'SCOTT.TRG_BU_BBB'


SQL>