Mongoose - 在父文档中引用嵌入的 id答案

【问题标题】：Mongoose - reference an embedded id in the parent documentMongoose - 在父文档中引用嵌入的 id
【发布时间】：2015-02-28 20:48:48
【问题描述】：

到目前为止，我有这个简单的架构：

var room = new Schema(
  {
    name: { type: String, default: null, trim: true }
  });

var event = new Schema({
  name:            { type: String, default: null, trim: true },
  startDate:       Date,
  endDate:         Date,
  logo:            { type: Boolean, default: false },
  public:          { type: Boolean, default: false },
  rooms:           [room]
  sessions:        [
    {
      title:       { type: String, default: null, trim: true },
      description: { type: String, default: null, trim: true },
      date:        Date,
      start:       Number,
      end:         Number,
      room:        { type: Schema.Types.ObjectId, ref: 'room' }
    }
  ]
});

我知道如何引用另一个集合，但如何引用父文档中的嵌入 ID？

我知道这个架构不正确，因为即使我删除了一个房间，房间引用也不会从引用它的会话中删除。

提前致谢！

【问题讨论】：

标签： node.js mongodb mongoose

【解决方案1】：

您可以在房间架构中创建对事件的引用。然后在您对主父房间执行删除操作时使用 schema.pre 中间件删除 session.room 值。（确保从主房间删除 eventid架构）。另请参阅Removing many to many reference in Mongoose

var room = new Schema({
    name: {
        type: String,
        default: null,
        trim: true
    },
    eventid: {
        type: Schema.Types.ObjectId, //Set reference to event here.
        ref: 'event'
    }
});

room.pre('remove', function(next) {//event is the schema name.
    this.model('event').update({; //this will have all the models,select the event 
            sessions.room: this._id//will have the room id thats being deleted
        }, {
            $pull: {
                sessions.room: this._id//removes that array from the event.sessions.room
            }
        }, {
            multi: true
        },
        next();//continues and completes the room.remove.
    );
});

【讨论】：