Flutter -如何在Firestore中首次添加(创建)嵌套集合，然后添加字段(更新集合)

import 'package:cloud_firestore/cloud_firestore.dart';

void addNestedCollection() async {
  // 初始化 Firestore 实例
  FirebaseFirestore firestore = FirebaseFirestore.instance;

  // 创建一个文档
  DocumentReference parentDocRef = await firestore.collection('parentCollection').add({
    'name': 'Parent Document',
  });

  // 在父文档中添加嵌套集合
  CollectionReference childCollectionRef = parentDocRef.collection('childCollection');
  await childCollectionRef.add({
    'name': 'Child Document',
  });

  print('Nested collection added successfully!');
}

void updateDocument() async {
  // 初始化 Firestore 实例
  FirebaseFirestore firestore = FirebaseFirestore.instance;

  // 获取父文档的引用
  DocumentReference parentDocRef = firestore.collection('parentCollection').doc('parentId');

  // 更新父文档并添加新字段
  await parentDocRef.update({
    'newField': 'New Value',
  });

  print('Document updated successfully!');
}

// 确保 Firestore 实例已正确初始化
FirebaseFirestore firestore = FirebaseFirestore.instance;

// 检查 Firestore 安全规则
service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if request.auth != null;
    }
  }
}

// 确保文档存在
DocumentSnapshot snapshot = await parentDocRef.get();
if (snapshot.exists()) {
  await parentDocRef.update({
    'newField': 'New Value',
  });
} else {
  print('Document does not exist!');
}