Oracle觸發器聯合唯一約束

oracle支援可為空字端的唯一約束呢？下面就是用觸發器作出的限制語句，僅供參考：

create or replace trigger tg_completion_test

before insert or update on bz_funds_voucher
for each row --行觸發，沒有本行則為語句級觸發
declare
too_many exception;
pragma exception_init(too_many, -20001);
v_exist_count number := 0;
begin
select count(*)
into v_exist_count
from bz_funds_voucher t
where t.document_code is not null
and t.territory_code = :new.territory_code
and t.document_code = :new.document_code ;
if v_exist_count > 0 then
end if;
end;

create or replace trigger tg_bz_rent_payment_voucher

before insert or update on bz_rent_payment_voucher
for each row --行觸發，沒有本行則為語句級觸發
declare
too_many exception;
pragma exception_init(too_many, -20002);
v_exist_count number := 0;
begin
select count(*)
into v_exist_count
from bz_rent_payment_voucher t
where
t.collection_way not in ('轉款', '優惠活動')
and t.create_date > to_date('2015-01-01', 'yyyy-mm-dd')
and t.serial_no is not null
and t.reserve_code is null
and t.serial_no = :new.serial_no ;
if v_exist_count > 0 then
end if;
end;

MySQL 新增唯一約束和聯合唯一約束

在mysql資料庫中，經常會碰到由於業務需要新增唯一鍵約束，唯一鍵約束，可以在乙個列上新增約束，也可以在多個列上新增唯一約束。1.建表時加上唯一性約束 create table t user id int 11 notnull auto increment username varchar 18 n...

oracle違反唯一約束

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唯一約束和檢查約束（oracle）

1.唯一約束和主鍵區別 主鍵字段值必須是非空的 唯一約束允許有乙個空值 2.唯一約束關鍵字 unique 3.在建立表時設定唯一約束 constraint constraint name unique column name 4.在修改表新增唯一約束 add constraint constrain...