Right way to store Schemas on Mongoose? - node.js

Question

I started learning some NodeJS, and how to make a REST API from Academind on YouTube, and learned what a relational and non-relational database is, etc.
With MongoDB, writes are rather cheap, so I want to minimize the number of reads that I do. At the moment I am trying to see how I could make an API, that will be for an app that's similar to discord's, although it'll be for fun.
Is this the right way to make a Schema?
const mongoose = require('mongoose')
const userSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true, unique: true},
email: { type: String, required: true },
password: { type: String, required: true }, // TODO: Hashing, etc
guilds: [{
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true},
channels: [{
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true},
// Only the X most recent messages
messages: [{
_id: mongoose.Schema.Types.ObjectId,
message: {type: String, required: true},
user: {
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true}
}
}]
}],
// Only an X amount of users
users: [{
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true}
}]
}]
})
module.exports = mongoose.model('User', userSchema)
And then for the Guilds,
const mongoose = require('mongoose')
const guildSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true},
channels: [{
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true},
// Only an X amount of messages
messages: [{
_id: mongoose.Schema.Types.ObjectId,
message: {type: String, required: true},
user: {
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true}
}
}]
}],
// All the users
users: [{
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true}
}]
})
module.exports = mongoose.model('Guild', guildSchema)
Channel Schema
const mongoose = require('mongoose')
const channelSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true },
guild: {
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true },
channels: [{
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true }
}],
// The users of the guild, or just the channel?
// Could add a users object outisde of the guild object
users: [{
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true }
}]
}
})
module.exports = mongoose.model('Channel', channelSchema)
And finally for the messages
const mongoose = require('mongoose')
const messageSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
user: {
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true}
},
message: {type: String, required: true},
channel: {
guild: {
_id: mongoose.Schema.Types.ObjectId,
name: {type: String, required: true}
// Store more data for each message?
}
}
})
module.exports = mongoose.model('Message', messageSchema)
I am not sure if this is how a non-relational schema should look like. If it's not, how would I go about to store the data that I need?
Also, let's say that I POST a message on channel X on guild Y with the users A B and C, how would I go about to update all the entries, to add a message?
I've only used the User.find({_id: id}).exec().then().catch() so far, so I am not sure how to go about to update them.
Thanks in advance!

Answer 1

The messages collection should be on its own, do not embed it into any collection. This is not a good idea to embed data that will grow without limit.
The idea to store the last 5 messages into other collection looks painful to implement.
Embed denormalised data from all collections into the users collection seems like a problem when you will have to update guilds, channels, guilds users.
You may embed channels into guilds. Channels would not grow without a limit, should be a reasonable amount, less than 100 of channels per guild and probably it always used with a guild that they belong to. If not, consider not to embed channels into guilds.
The power of mongodb is to build the schema that reflects how your app is using data. I would recommend starting with normalized data. And when problems with creating, reading, updating, deleting data will occur then make appropriate changes in your mongoose schema to solve the problem. Premature optimization will only hurts in the long run.
As always an answer depends on details. Since I do not know all details I would recommend three part article by William Zola, Lead Technical Support Engineer at MongoDB. part 1 part 2 part 3