如何在nestjs中填充猫鼬引用？

Question

我定义了人物和故事模式：

    @Schema()
    export class Person extends Document {
      @Prop()
      name: string;
    }
    export const PersonSchema = SchemaFactory.createForClass(Person);
    
    
    @Schema()
    export class Story extends Document {
    
      @Prop()
      title: string;
    
      @Prop()
      author:  { type: MongooseSchema.Types.ObjectId , ref: 'Person' }
    
    }
    export const StorySchema = SchemaFactory.createForClass(Story);

在我的服务中，我实现了保存和读取功能：

        async saveStory(){
        const newPerson = new this.personModel();
        newPerson.name  = 'Ian Fleming';
        await newPerson.save();
        const newStory  = new this.storyModel();
        newStory.title = 'Casino Royale';
        newStory.author = newPerson._id;
        await newStory.save();
      }
    
      async readStory(){
        const stories = await this.storyModel.
            findOne({ title: 'Casino Royale' })
        console.log('stories ',stories);
      }

当我运行 readStory() 时，我得到以下输出：

     stories  {
      _id: 5f135150e46fa5256a3a1339,
      title: 'Casino Royale',
      author: 5f135150e46fa5256a3a1338,
      __v: 0
    }

当我在查询中添加

populate('author')

时，我的作者为 null:

     stories  {
      _id: 5f135150e46fa5256a3a1339,
      title: 'Casino Royale',
      author: null,
      __v: 0
    }

如何使用引用的人员文档填充作者字段？

Answer 1

在对 Nestjs 中的猫鼬参考进行大量阅读和测试之后。我认为已接受的答案可以改进。我将分两步展示这一点。第一步是显示 MongooseSchema 的声明，并包含 @illnr 关于作者属性的评论，以使用

Types.ObjectId

而不是

MongooseSchema.Types.ObjectId

。

import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
import { Document, Types, Schema as MongooseSchema } from 'mongoose';

@Schema()
export class Story extends Document {

  @Prop()
  title: string;

  @Prop({ type: MongooseSchema.Types.ObjectId , ref: 'Person' })
  author:  Types.ObjectId 

}

export const StorySchema = SchemaFactory.createForClass(Story);

作为第二步，我认为使用 Person 类作为作者属性的类型可以提高可读性，如下所示。

import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
import { Document, Types, Schema as MongooseSchema } from 'mongoose';
import { Person } from './person.schema'

@Schema()
export class Story extends Document {

  @Prop()
  title: string;

  @Prop({ type: MongooseSchema.Types.ObjectId , ref: 'Person' })
  author:  Person

}

export const StorySchema = SchemaFactory.createForClass(Story);

Answer 2

找到了。 我的错误在于定义模式。 应该是：

@Schema()
export class Story extends Document {
  @Prop()
  title: string;
    
  @Prop({ type: MongooseSchema.Types.ObjectId , ref: 'Person' })
  author:  MongooseSchema.Types.ObjectId  
}

Answer 3

以上对我来说都不起作用，我不得不使用

populate()

。参考来自 https://dev.to/mossnana/nestjs-with-mongoose-populate-4mo7?signin=true

完整代码和结构示例 用户.service.ts

import { User, UserDocument } from 'src/schemas/user.schema';
import { Role, RoleDocument } from 'src/schemas/role.schema';

...

constructor(
    @InjectModel(User.name) private userModel: Model<UserDocument>,
    @InjectModel(Role.name) private roleModel: Model<RoleDocument>,
    private roleService: RolesService
  ) {}


async findOne(id: string) {
    return await this.userModel.findOne({ _id: id }).populate('role', '', this.roleModel).exec();
}

用户.schema.ts

import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
import * as mongoose from 'mongoose';
import { Role } from './role.schema';

export type UserDocument = User & mongoose.Document;

@Schema()
export class User {
  @Prop({ required: true, type: String })
  email: string;

  @Prop({ type: String })
  name: string;

  @Prop({ type: mongoose.Schema.Types.ObjectId, ref: 'Role' })
  role: Role;
}

export const UserSchema = SchemaFactory.createForClass(User);

角色.schema.ts

export type RoleDocument = Role & mongoose.Document;

@Schema()
export class Role {
  @Prop({ type: String, required: true, unique: true, index: true })
  name: string;

  @Prop({ type: [String], required: true })
  permissions: string[];
}

export const RoleSchema = SchemaFactory.createForClass(Role);

Answer 4

在我的回复中，我定义了预订和任务分配者模式。我使用 UUID（生成唯一字符串）而不是 ObjectID 来覆盖每个 MongoDB 文档的默认 ObjectID。由于taskerID属性，我使用类型为

string

而不是

Types.ObjectId

。

预订.schema.ts

import { Prop, Schema, SchemaFactory } from "@nestjs/mongoose";
import mongoose, { HydratedDocument } from "mongoose";

export type BookingDocument = HydratedDocument<Booking>;

@Schema({ collection: "booking" })
export class Booking {
  @Prop({ required: true })
  _id: string;

  @Prop({required: true, type: mongoose.Schema.Types.String, ref: "Tasker"})
  taskerID: string;
}

export const BookingSchema = SchemaFactory.createForClass(Booking);

export const BookingModel = {name: Booking.name, schema: BookingSchema};

tasker.schema.ts

import { Prop, Schema, SchemaFactory } from "@nestjs/mongoose";
import { HydratedDocument } from "mongoose";

export type TaskerDocument = HydratedDocument<Tasker>;

@Schema({ collection: "tasker" })
export class Tasker {
  @Prop({ required: true })
  _id: string;

  @Prop({ required: true })
  phone: string;

  @Prop({ required: true })
  name: string;
}

export const TaskerSchema = SchemaFactory.createForClass(Tasker);

export const TaskerModel = {name: Tasker.name, schema: TaskerSchema};

我填充了猫鼬参考，如下例所示。

预订.service.ts

import { Injectable } from "@nestjs/common";
import { InjectModel } from "@nestjs/mongoose";
import { Booking, BookingDocument } from "../db-module/schemas/booking.schema";
import * as mongoose from "mongoose";
import { Tasker, TaskerDocument } from "../db-module/schemas/tasker-user.schema";

@Injectable()
export class BookingService {
  constructor(
    @InjectModel(Booking.name)
    private bookingModel: mongoose.Model<BookingDocument>,
    @InjectModel(Tasker.name)
    private taskerModel: mongoose.Model<TaskerDocument>
  ) {}

  async findById(id: string): Promise<Booking> {
    const Booking = await this.bookingModel.findOne({ _id: id }).populate(
      "taskerID",
      "",
      this.taskerModel,
    ).exec();
    return Booking.toJSON();
  }
}