/** XXX CODING HORROR... */
根據您的需求,您可以使用一個更新視圖。您創建基表的視圖並向此視圖添加「而不是」觸發器,並直接更新視圖。
一些示例表:
create table party (
party_id integer,
employee_id integer
);
create table party_name (
party_id integer,
first_name varchar2(120 char),
last_name varchar2(120 char)
);
insert into party values (1,1000);
insert into party values (2,2000);
insert into party values (3,3000);
insert into party_name values (1,'Kipper','Family');
insert into party_name values (2,'Biff','Family');
insert into party_name values (3,'Chip','Family');
commit;
select * from party_v;
PARTY_ID EMPLOYEE_ID FIRST_NAME LAST_NAME
1 1000 Kipper Family
2 2000 Biff Family
3 3000 Chip Family
...然後創建一個可更新視圖
create or replace view party_v
as
select
p.party_id,
p.employee_id,
n.first_name,
n.last_name
from
party p left join party_name n on p.party_id = n.party_id;
create or replace trigger trg_party_update
instead of update on party_v
for each row
declare
begin
--
update party
set
party_id = :new.party_id,
employee_id = :new.employee_id
where
party_id = :old.party_id;
--
update party_name
set
party_id = :new.party_id,
first_name = :new.first_name,
last_name = :new.last_name
where
party_id = :old.party_id;
--
end;
/
現在,您可以直接更新視圖...
update party_v
set
employee_id = 42,
last_name = 'Oxford'
where
party_id = 1;
select * from party_v;
PARTY_ID EMPLOYEE_ID FIRST_NAME LAST_NAME
1 42 Kipper Oxford
2 2000 Biff Family
3 3000 Chip Family
感謝你,尼克。令人遺憾的是,除了用同樣的where子句創建三個不同的更新語句之外,還有很多工作要做。這更難以維護(表格,視圖和觸發器與具有三條更新語句的一個過程)。直到有更好的解決方案出現,你的勝利。 ;-) – 2010-04-23 16:45:58