Mongoose(mongoDB) Linking multiple schema's - node.js

Question

Im relatively new to MongoDB and Mongoose. Im much used to MySQL so in used to inner joining tables on calls. Ive read a lot that you can link two Mongoose Schemas to achieve the same outcome. How would like like the two schemas together to when I make a call to get a chore by id it'll return the chore and then for the assignedTo & createdBy have the user scheme data for the said userId?
Chore Schema
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var ChoreSchema = new Schema({
title: {
type: String,
required: true
},
desc: {
type: String,
required: true
},
time: {
type: Number,
required: true
},
reaccurance: {
type: [{
type: String,
enum: ['Daily', 'Weekly', 'Bi-Weekly', 'Monthly']
}]
},
reward: {
type: Number,
required: true
},
retryDeduction: {
type: Number,
required: false
},
createdDate: {
type: Date,
default: Date.now
},
createdBy: {
type: String,
required: true
},
dueDate: {
type: Date,
required: true
},
status: {
type: [{
type: String,
enum: ['new', 'pending', 'rejected', 'completed', 'pastDue']
}],
default: ['new']
},
retryCount: {
type: Number,
default: 0,
required: false
},
rejectedReason: {
type: String,
required: false
},
familyId: {
type: String,
required: true
},
assignedTo: {
type: String,
required: false,
default: ""
}
});
let Chores = module.exports = mongoose.model('Chores', ChoreSchema);
module.exports.get = function (callback, limit) {
Chores.find(callback).limit(limit);
};
User Schema
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var UserSchema = new Schema({
firstName: {
type: String,
required: true
},
lastName: {
type: String,
required: true
},
role: {
type: [{
type: String,
enum: ['Adult', 'Child']
}]
},
birthday: {
type: String,
required: false
},
familyId: {
type: String,
required: true
},
balance: {
type: Number,
required: true,
default: 0.00
}
});
let Users = module.exports = mongoose.model('Users', UserSchema);
module.exports.get = function (callback, limit) {
Users.find(callback).limit(limit);
};
Im trying to link ChoreSchema.createdBy & ChoreScheme.assignedTo by UserSchema._id
How I make the call in Node.js:
exports.index = function(req, res) {
Chore.get(function(err, chore) {
if (err)
res.send(err);
res.json({
message: 'Chore List',
data: chore
});
});
};

Answer 1

Mongoose has a more powerful alternative called populate(),
which lets you reference documents in other collections.
https://mongoosejs.com/docs/populate.html
Here is how you can link ChoreSchema.createdBy and ChoreScheme.assignedTo by UserSchema._id
var mongoose = require('mongoose');
const { Schema, Types } = mongoose;
var UserSchema = new Schema({
firstName: { type: String, required: true },
...
})
var ChoreSchema = new Schema({
title: { type: String, required: true },
...
//The ref option is what tells Mongoose which model to use during population
assignedTo: { type: Types.ObjectId, ref: 'Users' },
createdBy: { type: Types.ObjectId, ref: 'Users' },
})
let Chores = mongoose.model('Chores', ChoreSchema);
let Users = mongoose.model('Users', UserSchema);
Then in your express route handler you can populate assignedTo & createdBy like this
router.get('/chores/:id', function (req, res) {
const choreId = req.params.id;
Chores.find({ _id: choreId })
.populate('createdBy') // populate createdBy
.populate('assignedTo') // populate assignedTo
.exec(function (err, chore) {
if(err) {
return res.send(err)
}
res.json({ message: 'Chore List', data: chore });
});
})