Flutter:如何从Sembast数据库中存储和检索单个项目/对象

dependencies:
  sembast: ^2.4.0
  sembast_sqflite: ^2.4.0

import 'package:path/path.dart';
import 'package:sembast/sembast.dart';
import 'package:sembast_sqflite/sembast_sqflite.dart';

class DatabaseHelper {
  static final DatabaseHelper _instance = DatabaseHelper._internal();
  static DatabaseFactory databaseFactory = databaseFactorySqflite;

  factory DatabaseHelper() {
    return _instance;
  }

  DatabaseHelper._internal();

  Future<Database> initDatabase() async {
    String databasePath = await getDatabasesPath();
    String path = join(databasePath, 'my_database.db');
    Database database = await databaseFactory.openDatabase(path);
    return database;
  }
}

class Project {
  int id;
  String name;
  String description;

  Project({this.id, this.name, this.description});

  Map<String, dynamic> toMap() {
    return {
      'id': id,
      'name': name,
      'description': description,
    };
  }

  static Project fromMap(Map<String, dynamic> map) {
    return Project(
      id: map['id'],
      name: map['name'],
      description: map['description'],
    );
  }
}

import 'package:sembast/sembast.dart';
import 'package:sembast_sqflite/sembast_sqflite.dart';

DatabaseHelper databaseHelper = DatabaseHelper();

Future<void> saveProject(Project project) async {
  Database database = await databaseHelper.initDatabase();
  StoreRef store = intMapStoreFactory.store('projects');
  await store.record(project.id).put(database, project.toMap());
}

Future<Project> getProject(int id) async {
  Database database = await databaseHelper.initDatabase();
  StoreRef store = intMapStoreFactory.store('projects');
  Map<String, dynamic> data = await store.record(id).get(database);
  return Project.fromMap(data);
}