Firestore:获取在何处找到的文档的子集合 [英] Firestore: Get subcollection of document found with where

问题描述

我正在尝试将文档收集到一个子集合中，该子集合是使用.where函数找到的文档的一部分

I am trying to get the documents inside an subcollection which is part of an document found with the .where function

示例:

• RootColl/
  • 文档A/
    • SubColl 1
      • Doc 1
      • Doc 2
      • Doc 3
      • RootColl/
        • Doc A/
          • SubColl 1
            • Doc 1
            • Doc 2
            • Doc 3
            • 文档
            • SubColl 1
              • Doc 1
              • Doc 2
              • Doc 3
              • SubColl 1
                • Doc 1
                • Doc 2
                • Doc 3
                • 文档

                我想从文档中获取字段级别== 1的SubColl 1下的所有文档

                I want to get all the documents under SubColl 1 from the doc with the field level == 1

                我正在尝试这样做:

                db.collection("RootColl").where("field", "==", "1").collection("SubColl 1").get()

                但是这样做我得到了错误

                But by doing that i get the error

                Uncaught TypeError: db.collection(...).where(...).collection is not a function

                按照弗兰克·范·普菲伦的建议，我遇到了同样的错误，收藏"不是一个函数

                EDIT 1: By following Frank van Puffelen suggestion, i get the same error, "collection" is not a function

                • 当前代码
                • 错误
                • Current Code
                • Error

                推荐答案

                子集合位于特定文档下.您现在共享的查询指向到许多文档.您将需要执行查询以确定它指向的文档，然后遍历结果，并获取每个文档的子集合.

                A sub-collection lives under a specific document. A query as you've shared now points to a number of documents. You'll need to execute the query to determine what documents it points to, then loop over the results, and get the sub-collection for each document.

                在代码中:

                var query = db.collection("RootColl").where("field", "==", "1");
                query.get().then((querySnapshot) => {
                  querySnapshot.forEach((document) => {
                    document.ref.collection("SubColl 1").get().then((querySnapshot) => {
                      ...
                    });
                  });
                });
                

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