Firestore无法检索完整的数据值 [英] Firestore is not retrieving the complete data values

问题描述

图1显示了我的数据库的层次结构.

Image 1 shows the hierarchy of my DB.

我正在尝试检索课程的名称[Android，Branding ....].斜体(品牌，其他)中的数据由后端添加-发布命令，而其他数据则通过键入添加.如屏幕快照2所示，仅检索非斜体数据时，我无法弄清楚为什么会发生这种情况.屏幕截图2还显示了我正在使用的查询.请帮忙!!

I am trying to retrieve the names of the courses [Android, Branding .... ]. The data in italics(Branding, others) gets added by the backend - post commands, and the other data is added typing. While retrieving only the non - italics data gets retrieved as seen in screenshot 2. I can not figure out why this might be happening. Screenshot 2 also shows the query I am using to the same. Please help !!

谢谢.

推荐答案

如屏幕截图2所示，仅检索非斜体数据时，

While retrieving only the non - italics data gets retrieved as seen in the screenshot 2

以斜体显示的文档ID-表示实际上没有文档在其位置；但是，有些子集合在其下组织有文档.Firestore查询仅返回非空文档.

Document IDs shown in italics - means there is not actually a document in its place; however, there are subcollections with documents organized underneath them. Firestore query returns only non-empty documents.

您可以选择两种选择，

• 如果您确定自己的文档ID，可以直接访问集合

firestore.collection('users/groups/groupID/courses/others/courses').get()

• 使用 collectionGroup 查询；但似乎您有许多具有相同ID courses 的收藏集，因此它可能会使所有内容恢复原状，可能不适合您！我建议您阅读 firabase文档这是局限性
• Using collectionGroup queries; but it seems you have many collections with same ID courses, so it might retreive all and might not be suitable for you! I recommend you to read firabase doc for it's limitations

firestore.collectionGroup('courses').get()

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