猫鼬多对多关系

Question

I am completely new to Node.js and Mongoose and I came up to this problem of having

Event and User and a relationship where the User can go to any Event and Event can have many participating users.

Any time the user would want to attend an Event I could add the Event id to User's array of events and simultaneously add the User to the Event's array of users but I think that I want to avoid this approach because I would store the same information twice.

On the other hand I could only store the User to the Event's array of users and use virtual mapping to retrieve all the User's events but I find this approach quite time consuming. It seems to me that I would have to go through each Event and then through all of its participating users to find out if the user really is participating or not. Anyways if there is a way to do this using the virtual function, i don't know how to map the localField: userId to the array of the Event's foreignField: participants .

What would be the correct approach to this problem?

Answer 1

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const eventSchema = Schema({
  name: String,
  user: [{ type: Schema.Types.ObjectId, ref: 'User' }]
});

const userSchema = Schema({
  name: String,
  event: [{ type: Schema.Types.ObjectId, ref: 'Event' }]
});

const Event = mongoose.model('Event', eventSchema);
const User = mongoose.model('User', userSchema);

use can read more here https://mongoosejs.com/docs/populate.html