休眠并删除所有 [英] hibernate and delete all

问题描述

在Hibernate中删除表中的所有行的最佳方法是什么？

如果我遍历集合并调用 session.delete（）它不符合我的要求。

如果我使用另一个选项 session .createQuery（delete ...）它不影响持久化上下文。

当我不应该使用这些方法时更好的变体？

解决方案

• 如果您没有任何级联，请使用HQL delete 删除enityName


• 如果您有级联，则迭代集合并单独删除每个集合。
  
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问题在于hibernate在内部处理级联，而不是将其留给数据库。所以发送一个查询不会触发内部级联，因此你将有不一致/孤儿。





如果性能如此重要（毕竟不是每天都会截断一个表），那么每个级联可以有多个HQL删除 - 即手动处理级联。




What is the best way to delete all rows in a table in Hibernate?

If I iterate over a collection and call session.delete() it's not performing to my knowledge.

If I use another option session.createQuery("delete ...") it doesn't affect persistence context.

When I should use these methods if there is no better variant?

解决方案

• if you don't have anything to cascade, use the HQL delete DELETE FROM enityName
• if you have cascades, iterate the collection and delete each one individually.

The problem lies in the fact that hibernate handles cascades internally, rather than leaving this to the database. So sending a query won't trigger the internal cascades, hence you will have inconsistencies / orphans.

If performance is so crucial (after all it's not everyday that one truncates a table), then you can have more than 1 HQL delete for each cascade - i.e. handling the cascades manually.

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