无法截断表，因为它正被 FOREIGN KEY 约束引用?

2021-12-02 00:00:00 sql-server-2005 foreign-keys tsql sql-server truncate

使用MSSQL2005，如果先截断子表(FK关系主键的表)，是否可以截断带有外键约束的表?

Using MSSQL2005, can I truncate a table with a foreign key constraint if I first truncate the child table (the table with the primary key of the FK relationship)?

我知道我可以

  • 使用不带where子句的DELETE，然后RESEED标识(或)
  • 删除 FK，截断表，然后重新创建 FK.

我认为只要在父表之前截断子表，不执行上述任一选项就可以了，但是我收到此错误:

I thought that as long as I truncated the child table before the parent, I'd be okay without doing either of the options above, but I'm getting this error:

无法截断表TableName"，因为它正被外键约束引用.

Cannot truncate table 'TableName' because it is being referenced by a FOREIGN KEY constraint.

推荐答案

正确；您不能截断具有 FK 约束的表.

Correct; you cannot truncate a table which has an FK constraint on it.

通常我的流程是:

  1. 放弃约束
  2. 截断桌子
  3. 重新创建约束.

(当然，一切都在交易中.)

(All in a transaction, of course.)

当然，这仅适用于子项已经被截断的情况.否则我会走不同的路线，完全取决于我的数据是什么样的.(变量太多，无法进入.)

Of course, this only applies if the child has already been truncated. Otherwise I go a different route, dependent entirely on what my data looks like. (Too many variables to get into here.)

原始海报确定了为什么会这样；请参阅此答案 了解更多详情.

The original poster determined WHY this is the case; see this answer for more details.

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