oracle触发器中定义变量

----------------------------------------------------------
--每进行一次交易，就要调用触发器，自动扣除或增加账户金额
----------------------------------------------------------
create table account
(
  customerName varchar2(30) primary key,
  cardID varchar2(8),
  currentMoney number
);
insert into account values('Daivd','10010001',5000);
insert into account values('Jason','10010002',3000);

create table trans
(
  transDate date,
  cardID varchar2(8),
  transType varchar2(10),
  transMoney number
);
insert into trans 
values(sysdate,'10010001','取款',1000);

create or replace trigger trans_trigger
before insert
on trans
for each row
declare
  v_currentMoney account.currentMoney%type;
begin
  --判断类型
  if :new.transType='取款' then
   --取款
   select currentMoney into v_currentMoney
   from account
   where cardID=:new.cardID;
   
   if v_currentMoney < :new.transMoney then
     raise_application_error(-20001,'余额不足');
   end if;
   
   update account
   set currentMoney=currentMoney-:new.transMoney
   where cardID=:new.cardID;
  else
   --存款
   update account
   set currentMoney=currentMoney+:new.transMoney
   where cardID=:new.cardID;
  end if;
exception  
  when no_data_found then
    raise_application_error(-20002,'无效的帐户');
end;


--模式(schema)级触发器
create or replace trigger schema_trigger
before drop
on schema
begin
  dbms_output.put_line('schema_trigger called');
  dbms_output.put_line(ora_dict_obj_name);
  dbms_output.put_line(ora_dict_obj_type);
  
  if ora_dict_obj_name='ACCOUNT' then
    raise_application_error(-20003,'ACCOUNT表不能被删除');
  end if;
end;

drop table account;
--ora_dict_obj_name 操作对象名称
--ora_dict_obj_type 操作对象类型

--启用触发器
alter trigger schema_trigger enable;
--禁用触发器
alter trigger schema_trigger disable;

-------------------------自己写的-------------------

-----------------------测试表---------------------
create table Test
(
iKey int,
iValue int,
primary key(iKey)
);
create table Test_Log
(
iKey int,
iClass varchar(4)
);
create trigger Test_Tri after insert on Test
for each row
begin
   if :new.iValue>90 then
   insert into Test_log values(:new.iKey,1);
   end if;
end;

insert into Test values(12,120);
insert into Test values(18,60);
insert into Test values(10,90);