是否可以在SQL中将主键更新为null [英] Is it possible to update a primary key to null in SQL

问题描述

我在SQL Server 2008中有一个带有主键的表.
当我尝试将主键更新为null时，这正在发生，这是SQL的功能，您可以将主键更新为null吗?

I have a table with a primary key in SQL Server 2008.
When I try to update the primary key to null, it is happening, Is this a feature of SQL that you can update the primary key to null?

推荐答案

简而言之，主键永远不能为空.

如果需要有时可能为空的键，请考虑使用唯一键.

参考文献:
-主键 [唯一键 [

To simply put it, primary key can never be null.

If you need a key that can sometimes be null, consider using a unique key.

References:
- Primary key[^]
- Unique key[^]

绝对不是我亲爱的...

主键列始终保持数据不为空和唯一.

Absolutely not my dear...

Primary key column always keeps data NOT NULL and UNIQUE.

谢谢！
我想我出了问题所在.通过UI如何在主列中插入一个空字符串.因此，它实际上不是空值.

Thanks!
I think I got where I was going wrong. Some how through the UI, an empty string was getting inserted into the primary column . So, it was not actually a null value.

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