如何删除包括所有孩子的实体 [英] How to delete an entity including all children

问题描述

我想对数据存储中的实体进行级联删除。我的意思是，所有儿童和间接儿童也将被删除。我最初认为这将是默认行为，但不知何故... ...

我的想法是这样的：

  ndb.delete_multi（ndb.Model.query（ancestor = key）.iter（keys_only = True））
  

但是模型应该是一个通配符，因为实体可以是几个类的父类......

I还想在删除实体时删除BlobKeyProperties。为此，我想到
：
$ b $ pre code @classmethod
def _post_delete_hook（cls，key，future） ：
＃通知他们失去了一位朋友

我应该用它来级联删除对于无情的祖先查询，请从 com / appengine / docs / python / ndb / queryclass＃构造函数rel =nofollow>查询类

  ndb.delete_multi（ndb.Query（ancestor = key）.iter（keys_only = True））
  

I不会对所有子实体使用级联删除。如果你有很多，那么它会慢得多（除非你想在任务中运行删除）。

I would like to do a cascading delete on an entity in the datastore. By this I mean all children and indirect children will also be deleted. I initially assumed this would be default behavior but somehow it is not...

My thought was something like this:

ndb.delete_multi(ndb.Model.query(ancestor=key).iter(keys_only = True))

But the Model should be a wildcard, because the entity can be the parent of several classes...

I would also like to delete BlobKeyProperties when deleting an entity. For this I was thinking about:

@classmethod
  def _post_delete_hook(cls, key, future):
  # inform someone they have lost a friend

which I should maybe use for cascading delete as well?

解决方案

For kindless ancestor queries create the query from the query class

ndb.delete_multi(ndb.Query(ancestor=key).iter(keys_only = True))

I wouldn't use the cascading delete for all child entities. If you have a lot then it will be much slower (unless you want to run the delete in a task).

这篇关于如何删除包括所有孩子的实体的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！