create trigger aa on a for update,insert as if update(a表字段) begin insert into b from (select * from inserted where not exists(select * from b))a,inserted end
create or replace trigger aa for insert before delete on a for each row declare num number(2); begin select count(*) into num from b where 条件; if num=0 then insert into b values(); end if; end;
for update,insert
as
if
update(a表字段)
begin
insert into b from (select * from inserted where not exists(select * from b))a,inserted
end
before delete on a
for each row
declare num number(2);
begin
select count(*) into num from b where 条件;
if num=0 then
insert into b values();
end if;
end;