Question

我定义了一个人物和故事模式：

@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，得到以下输出：

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

当我向查询中添加populate('author')时，作者为null：

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

如何用引用的“个人”文档填充“作者”字段？

Answer 1

在对 nestjs 中的 mongoose 引用进行大量阅读和测试之后。我认为可以改进接受的答案。我将分 2 个步骤展示这一点。第一步是显示 MongooseSchema 的声明，并包括@illnr 关于作者属性使用 Types.ObjectId 而不是 MongooseSchema.Types.ObjectId 的注释。

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。我的错误在于定义架构。应该是：

@Schema()
export class Story extends Document {

  @Prop()
  title: string;

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

}

如何在nestjs中填充猫鼬引用？

2 个答案: