Question

我想知道这种事情是否有效：

假设我有两张桌子：公司和地址。每家公司只能有一个地址。简化的架构看起来像这样。

COMPANIES
id
address_id
name
(...)

ADDRESSES
id
first_name
street
(...)

现在，我想在 COMPANIES.address_id - ＆gt;上添加外键。 ADDRESSES.id ON UPETE UP NULL更新CASCADE 。但我也希望在删除公司时删除该地址。所以另一种方式是 ADDRESSES.id - ＆gt; COMPANIES.address_id ON DELETE CASCADE 。这样安全吗？

Answer 1

也许，使用触发器代替外键，可以解决您的问题。

create trigger addr_delete
after delete on companies for each row
begin
   delete from addresses where id=old.address_id
end

MySQL双路外键？

1 个答案: