Firestore获取子集合父文档ID-JavaScript [英] Firestore get subcollection parent document ID - JavaScript

问题描述

我的Firestore数据库中具有以下结构:几个 UserLists 集合，其中包含 Users .每个用户可能都有一个 Notes 子集合.

I have the following structure in my Firestore DB: several UserLists collections, which hold the Users. Each user may have a Notes subcollection.

我正在做一个效果很好的子集合组查询，从整个Notes子集合中返回笔记.

I'm doing a subcollection group query that works well, returning notes from across the Notes subcollection.

我的问题是，从Notes子集合中检索到的Notes文档中，我可以获得父文档ID吗?在下面的示例中，该用户为User 1.使用JavaScript.

Collection: UserList 1
  Doc: User 1
    Subcollection: Notes
      Doc: Note 1

Collection: UserList 2
  Doc: User 1
    Subcollection: Notes
      Doc: Note 1

推荐答案

您可以使用以下方法之一:

You could use one of the following approaches:

  const query = ......;
  query
    .then(function(querySnapshot) {
      querySnapshot.forEach(function(doc) {
        console.log(doc.ref.path);
        console.log(doc.ref.parent.parent.id);
      });
    })

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在每个 QueryDocumentSnapshot 上，您可以使用 path 属性，它将返回完整路径，例如 UserList1/User1/Notes/Doc1 .

---

On each QueryDocumentSnapshot, you can use the ref property, which returns a DocumentReference. Then, on this DocumentReference you use the path property, which will return the full path, e.g. UserList1/User1/Notes/Doc1.

或者您使用 parent DocumentReference 的> 属性，该属性返回 parent 属性(这次是 CollectionReference 的属性)，以获取父 DocumentReference ，然后此父 DocumentReference 的 id 属性.

Or you use the parent property of the DocumentReference, which returns a CollectionReference, then you use again the parent property (of the CollectionReference this time) to get the parent DocumentReference and then the id property of this parent DocumentReference.

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