消防仓库中的参考类型

Question

我正在尝试在firestore中实现文档引用。我创建了两个集合：Customers和Purchased-Property。每次在Purchased-Property集合中创建新文档时，我如何引用Purchased-Property_Customer_id中的Customer_id。代码如下所示：

const CustomerDoc = firebase.firestore().collection("Customers").doc()
CustomerDoc.set({
Customer_id: CustomerDoc.id,
Customer_Name: Name
Customer_PhoneNumber: PhoneNumber
})
const PurchasedPropertyDoc = firebase.firestore().collection("Purchased-Property").doc()
PurchasedPropertyDoc.set({
Purchased_Property_id: PurchasedPropertyDoc.id,
Purchased_Property_Name: Property_Name,
Purchased_Property_Location: Property_Location,
Purchased_Property_Customer_Id: Customer_Id   //How do i make  reference to this Customer_Id in the Customers collection everytime a new document under the Purchased-Property collection is made 


})

Answer 1

CustomerDoc是DocumentReference对象。每个DocumentReference都有一个id属性。你可以这样简单地使用它：

PurchasedPropertyDoc.set({
Purchased_Property_id: PurchasedPropertyDoc.id,
Purchased_Property_Name: Property_Name,
Purchased_Property_Location: Property_Location,
Purchased_Property_Customer_Id: CustomerDoc.id
})

这与您在第一个文档中首次使用CustomerDoc.id的方式没有什么不同。如果在创建文档时没有此引用，则无法建立关联。

Answer 2

您必须创建一个ref，如：

const CustomerRef = db.collection( "users" ).doc( userId )

然后设置为Purchased_Property_Customer_Id:CustomerRef