我应该使用CASCADE DELETE规则吗？ [英] Should I use the CASCADE DELETE rule?
问题描述
Duplicate of: When/Why to use Cascading in SQL Server?
我一直很害怕使用DELETE CASCADE，但是随着我变得更加自信（懒惰：D） ，我在想它有多糟，是使用它的最佳实践，还是应该避免使用它并以老式的方式（使用存储过程）清理我的外键等？
I've always been too scared to use DELETE CASCADE, but as I get more confident (lazy :D), I'm thinking how bad can it be, is it best practise to use it or should I avoid it and clean up my foreign keys etc the old fashioned way (with stored procedures)?
推荐答案
ON DELETE CASCADE很好，但是仅当相关行确实是要删除的行的逻辑扩展名时。例如，DELETE ORDERS可以删除关联的ORDER_LINES，因为您显然想删除此顺序，该顺序由标题和一些行组成，因此可以。另一方面，DELETE CUSTOMER不应删除关联的ORDERS，因为ORDERS本身很重要，而不仅仅是客户的属性。
ON DELETE CASCADE is fine, but only when the dependent rows are really a logical extension of the row being deleted. For example, it's OK for DELETE ORDERS to delete the associated ORDER_LINES because clearly you want to delete this order, which consists of a header and some lines. On the other hand, DELETE CUSTOMER should not delete the associated ORDERS because ORDERS are important in their own right, they are not just attributes of a customer.
一种思考的方式大概是这样的：如果我发出DELETE X并且它也删除Y，我会快乐还是不快乐？而且，如果我发出DELETE X并被告知由于存在Y而无法删除X，我会为保护感到高兴吗？还是对不便感到恼怒？
One way to think about this is: if I issue DELETE X and it also deletes Y, will I be happy or unhappy? And if I issue DELETE X and am told "cannot delete X because Y exists" will I be glad of the protection, or irritated at the inconvenience?
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