with check(转)

假如我要为一个表中添加一个外键约束.语法如下

alter table dbo.employee with check add constraint [FK_employeeno] foreign key ([colorcode])

references dbo.color([colorcode])

其中的with check /nocheck 的作用: 指定表中的数据是否用新添加的或者重新启用的foregin key 或者check 进行验证.

check
:对添加验证之前的数据也进行验证检查.

nocheck
:对添加之前的数据不进行验证检查,只对添加验证之后的数据进行检查.不提倡使用nocheck
,因为这样破坏了数据库中数据的一致性.

时间： 2024-11-05 03:07:33

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