通过ID查询Firebase Firestore文档 [英] Query Firebase Firestore documents by the ID

问题描述

正如我从"Cloud Firestore数据模型"指南中获得的每个文件都由名称标识"一样.可以通过该文档标识符(名称或ID)查询集合吗?

As I got from 'Cloud Firestore Data Model' guide "each document is identified by a name." Is it possible to query a collection by that document identifier (which is the name or ID)?

例如，事物"集合中的文档具有ID:0、1、2等:

For example, documents in the collection "Things" have IDs: 0, 1, 2 etc.:

是否可以查询ID小于100的文档?

Is it possible to query documents which IDs are less than 100?

推荐答案

您可以使用特殊的哨兵FieldPath.documentId()通过documentId查询，例如:

You can query by documentId using the special sentinel FieldPath.documentId(), e.g.:

const querySnap = collection.where(firebase.firestore.FieldPath.documentId(), '<', '100').get();

但是请注意，文档ID是字符串，因此，这将包括ID为'0'或'1'的文档，而不是包含'2'的文档，因为按字典顺序'2'>'100'.

But be aware that document IDs are strings and therefore this will include documents with ID '0' or '1', but not '2' since '2' > '100' lexicographically.

因此，如果要进行数字查询，则需要将文档ID作为文档中的数字字段编写，然后对其进行常规查询.

So if you want a numeric query, you'll need to write the document ID as a numeric field in the document and then do a normal query on it.

这篇关于通过ID查询Firebase Firestore文档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！