/** XXX CODING HORROR... */
根据您的需要,您可以使用可更新的视图。您创建基表的视图并向该视图添加“替代”触发器,然后直接更新视图。
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
...然后创建一个可更新的视图
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;
/
您现在可以直接更新视图...
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