Sql Server：使用“强制外键约束”的好处是什么？当它设置为“否”时 [英] Sql Server: What is the benefit of using "Enforce foreign key constraint" when it's set to "NO"?

问题描述

我知道RDBMS中强制执行外键约束的目的。但是在设置为否时有什么好处吗？

解决方案

在正常生产中，此设置应 / strong>设置为 NO 。

但是：当您开发或重组数据库时，或当你做例如您需要清理（清理）大量的大量数据，因此关闭外键约束可以将非有效数据加载到表中是有意义的。当然，正如我所说 - 你不应该长时间关闭这个设置 - 你应该继续清理数据，删除那些违反FK约束的行，或者更新它们的值所以他们匹配一个父行。

再次：在正常生产模式下，此设置不应该是 NO - 但是对于特定的任务，它可能有助于更容易地完成工作。请谨慎使用，并尽快将FK约束重新开启！

I know the purpose of "Enforce foreign key constraint" in RDBMS. But is there any benefit when it's set to "NO" ?

解决方案

In normal production, this setting should never be set to NO.

But: when you're developing, or restructuring a database, or when you do e.g. a large bulk load of data that you'll need to "sanitize" (clean up), then it can make sense to turn off foreign key constraints to allow "non-valid" data to be loaded into a table. Of course, as I said - you shouldn't keep that setting turned off for a long period of time - you should then proceed to clean up the data, either delete those rows that are in violation of the FK constraint, or update their values so they match a parent row.

So again: in "normal" production mode, this setting should never be NO - but for specific tasks, it might help get the job done more easily. Use it with caution, and always turn the FK constraints back on as soon as you can!

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