Firebase Cloud Firestore多对多关系 [英] Firebase Cloud Firestore Many to Many Relationships

问题描述

如何以多对多关系构造和查询Firebase Cloud Firestore中的数据?

How to structure and query data from Firebase Cloud Firestore in a many to many relationship?

我有公司和承包商.一个承包商可以为多个公司工作，而一个公司可以有多个承包商.这是直接的多对多关系.我希望能够回答有关公司和承包商的问题:

I have Companies and Contractors. A Contractor can work for more than one Company and a Company can have multiple Contractors. This is a straightforward many to many relationship. I want to be able to answer the questions about Companies and Contractors:

给出一个公司，他们是当前的承包商.给承包商一个他们要工作的公司.在Cloud Firestore中构造数据的正确方法是什么?

Given a Company, who are the current Contractors. Given a Contractor what Companies are they working for. What is the right way for structuring the data within Cloud Firestore?

推荐答案

您可以拥有带有地图字段的Contractor承包商项目，该地图字段的密钥为公司密钥，并且值可以是真，也可以是时间戳以帮助订购.并且公司的地图字段以承包商的钥匙作为钥匙并具有一定的价值. https://firebase.google.com/docs/firestore/solutions/中提到了此方法数组，当您尝试对它们进行过滤和排序时...

You can have Contractors item with a map field which has the key as the company key and the value can be true ou a timestamp to help ordering. And Companys with a map field with the contractors key as the key and some value. This aproach is mentioned in https://firebase.google.com/docs/firestore/solutions/arrays, when you try to filter and sort toghether...

Contractors
  companies
    idCompany1: timestamp
    idCompany2: timestamp
    idCompany3: timestamp

Companies
  contractors
    idContractor1: timestamp
    idContractor2: timestamp

在这种情况下，您可以进行任何查询，例如该公司承包商或该承包商的公司.像这样:

Is this case you can make any queries like this company contractors or the companies of this contractor. Like this:

fireStore.collection("Companies").whereField("contractors." + idContractor, isGreaterThan: 0).order(by: "contractors." + idContractor, descending: true)

是的，您必须在任何任务中同时更新两个地方

Yes you have to update both places in any task

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