我如何在集合中的文档中获取所有子集合

问题描述：

我正在寻找有关此问题的文档，但看起来相当多

i looking for document talk about this my problem but it look like quite quite a few

我有一个这样的收藏collection(user1)=> uid => document(collection(Product => uid)，nameUser .... bla bla)

i have one collection like this collection(user1)=>uid=>document( collection(Product => uid ),nameUser.... bla bla)

我让所有产品的文档用户1都非常容易，但是我如何与用户2，用户3一起获取并聚集到所有用户的阵列产品中?

i get all Product's document user1 this is quite easy but how i get this with user 2, user 3 and gathered into array product of all user?

我在下面尝试过此代码，但不理解

i have tried this code in below but it doesn't understand

getData = async () => {
    const a = [];
    await firebase.firestore().collection('user').doc().collection('Product').onSnapshot(sanpham => {

      sanpham.forEach((doc) => {
        a.push({ id: doc.id, data: doc.data() })
      })
    })
    this.setState({ data: a });
  }

答

如果要从所有 Product 集合中获取文档，则可以使用

If you want to get the documents from all Product collections, you can use a collection group query.

要使用它，请执行以下操作:

To use it, you'd do:

await firebase.firestore().collectionGroup('Product').onSnapshot(sanpham => {
  sanpham.forEach((doc) => {
    a.push({ id: doc.id, data: doc.data() })
  })
})

如果您想知道产品属于哪个用户，则可以使用以下方法确定该信息:

If you want to know which user a product belongs to, you can determine that with:

const productRef = doc.ref;
const productCollectionRef = productRef.parent;
const userRef = productCollectionRef.parent;
console.log(userRef.id);

我如何在集合中的文档中获取所有子集合

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