Oracle資料庫中的觸發器練習

一、表結構如圖，其中orders的orderid是主鍵，orderitem的orderid是外來鍵

-- orders表

create
table orders(
2 orderid number primary
key,
-- 編號
3 ordername varchar2(32)
,-- 名稱
4 orederprice number -- 單價5)
6/insert
into orders values(1
,'麵包',3
);insert
into orders values(2
,'衛衣',45
);insert
into orders values(3
,'手機'
,1800);
insert
into orders values(4
,'滑鼠',45
);insert
into orders values(5
,'鍵盤'
,130);
-- orderitem表
create
table orderitem(
2 orderitemid number primary
key,
-- 編號
3 orderid number references orders(orderid)
,-- 訂單編號
4 orderitemnumber number -- 訂購數量5)
6/insert
into orderitem values(1
,1,3
);insert
into orderitem values(2
,1,2
);insert
into orderitem values(3
,2,1
);insert
into orderitem values(4
,2,1
);insert
into orderitem values(5
,3,1
);insert
into orderitem values(6
,3,2
);insert
into orderitem values(7
,4,2
);insert
into orderitem values(8
,5,1
);insert
into orderitem values(9
,5,2
);

-- 觸發器

create
orreplace
trigger t1
before
insert
on orderitem
for each row
when
(new.orderitemnumber <1)
begin
:new.orderitemnumber:=1;
end;

-- 觸發觸發器

insert
into orderitem values(10
,5,0
);

-- 查詢一下

select
*from orderitem;

-- 觸發器

create
orreplace
trigger t2
before
delete
on orders
for each row
declare
n number;
begin
select
count(*
)into n from orderitem where orderid = :old.orderid;
if n >
0then
delete
from orderitem where orderid = :old.orderid;
endif
;end
;

-- 觸發觸發器

delete
from orders where orderid =
1;

賬戶資訊表(cardinfo)：卡號(主鍵)，密碼，餘額

create

table cardinfo(
2 cardinfo_id number primary
key,
3 cardinfo_pwd varchar2(32)
,4 cardinfo_balance number
5)6/
insert
into cardinfo values(1
,'123',32
);insert
into cardinfo values(2
,'123',45
);insert
into cardinfo values(3
,'123',23
);

create

table transinfo(
2 transinfo_id number primary
key,
3 transinfo_cardinfoid references cardinfo(cardinfo_id)
,4 transinfo_deal varchar2(32)
check
(transinfo_deal in
('支取'
,'存入'))
,5 transinfo_dealmoney number,
6 transinfo_dealdate date7)
8/insert
into transinfo values(1
,1,'支取',12
,sysdate)
;insert
into transinfo values(2
,1,'支取'
,100
,sysdate)
;insert
into transinfo values(3
,1,'存入'
,1000
,sysdate)
;insert
into transinfo values(4
,2,'存入'
,500
,sysdate)
;insert
into transinfo values(5
,2,'支取'
,100
,sysdate)
;insert
into transinfo values(6
,3,'支取'
,100
,sysdate)
;

-- 觸發器

create
orreplace
trigger t3
before
delete
on transinfo
for each row
when
(months_between(sysdate,old.transinfo_dealdate)
<1)
begin
-20002
,'這條交易記錄的時間不超過乙個月!');
end;

delete

from transinfo where transinfo_id =
3;

-- 觸發器

create
orreplace
trigger t4
after
insert
on cardinfo
for each row
declare
n number;
begin
select
max(transinfo_id)
into n from transinfo;
insert
into transinfo values
(n+1
,:new.cardinfo_id,
'存入',1
,sysdate)
;end
;

insert

into cardinfo values(4
,'123',54
);

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