firebase通过嵌套的子id获取树的URL [英] firebase get url by nested child id for tree like

问题描述

我在firebase中具有以下结构:

I have following structure in firebase:

 data/users/<id_user>/lists/<id_list>/children/<child1_id>/children/<child2_id>

如何在知道唯一的child2_id的情况下获取此完整URL?

how to get this full URL, knowing the only child2_id?

(最好是打字稿，angularfire 2)

(preferably typescript, angularfire 2)

推荐答案

Firebase Realtime数据库查询可以搜索位置的子节点.但是，您搜索的值必须位于每个孩子下方的固定路径上.

Firebase Realtime Database queries can search the child nodes of a location. But the value you search for must be at a fixed path under each child.

因此，如果您知道 data/users/< id_user>/lists/< id_list>/children/< child1_id> ，则可以使用查询以查找该子项下的子项child2_id .但是您无法跨多个嵌套的未知路径搜索 child2_id .

So if you know data/users/<id_user>/lists/<id_list>/children/<child1_id>, you can query to find the child under that with child2_id. But you can't search for child2_id across multiple nested unknown paths.

有关更多信息，请参见 Firebase Query Double Nested ，并且可能(取决于您的用例) Firebase查询，如果child的child包含值.

For more on this, see Firebase Query Double Nested, and possibly (depending on your use-case) Firebase query if child of child contains a value.

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