Mongo - How can I pass collection name to Schema while saving data - node.js

Question

I'm at my wits ends with mongoose here and not sure where i'm going wrong. Please help me out.
Say i define my schema like below:
const userDBSchema = new Schema({
userName: {
type:String
},
musicType: {
type: String,
},
}, { collection: 'userData' });
then run a post to the database, using this function:
exports.saveUser = (req, res) => {
const username = req.params.user;
const newUser = new UserInfoDb(req.body, {'collection': username});
newUser.save((err, response) => {
//save operation
});
};
i get this error:
{
"message": "document must have an _id before saving",
"name": "MongooseError"
}
Even when i manually define the id, with the following in my schema:
_id: {
type: mongoose.Schema.Types.ObjectId,
index: true,
required: true,
auto: true
},
I get this error:
{
"errors": {
"_id": {
"message": "Path `_id` is required.",
"name": "ValidatorError",
"properties": {
"message": "Path `_id` is required.",
"type": "required",
"path": "_id"
},
"kind": "required",
"path": "_id"
}
},
"_message": "userDB validation failed",
"message": "userDB validation failed: _id: Path `_id` is required.",
"name": "ValidationError"
}
Ultimately my goal is to That i can pass in the name of a collection I want to access from the POST, then write the body of my request into that collection. I have multiple collections I may need to write to at any given time. I've weighed up the decision to have one collection with everything but decided to go with multiple collections in order to store my data.

Answer 1

Can you confirm that you want to have multiple collections, which each user has his database collection? I think it's not a good decision!
This is my solution. You can create a model for each user with the same schema (userDBSchema you've created).
But you should be sure that you can generate unique collection names for each user. (such as a hash function or anything else)
I want to confirm again this is not really good way when creating for each user a collection to store his info.
Why?
If your system has millions of users, you will have millions of collections, it's very complicated to manage database. It's better with millions of document in a collection. This is my personal thought. Hope to help you
const mongoose = require('mongoose');
const userDBSchema = require('path/to/your/schema/declared');
// Generating unique collection name for each user
const getCollectionNameForUser = (username) => username;
exports.saveUser = (req, res) => {
const username = req.params.user;
const UserInfoDb = mongoose.model(getCollectionNameForUser(username), userDBSchema);
const newUser = new UserInfoDb(req.body);
newUser.save((err, response) => {
//save operation
});
};
Edit - Simple demo
This is my demo simple app, how to create dynamic model with a schema in mongoose, you can view full code and try it on your local database here https://gist.github.com/huynhsamha/4dcf00a1fba96ae7f186b606b33b7e9c
In my demo, I created a schema storing user info
const Schema = mongoose.Schema;
const UserInfoSchema = new Schema({
note: String,
timeline: { type: Date, default: Date.now }
});
And add log (with note) to each user via simple API GET
app.get('/add/:id/:note', async (req, res) => {
const { id, note } = req.params;
// Retrieve model which contain info documents of user with id
const UserInfo = mongoose.model('User_' + id, UserInfoSchema);
const log = new UserInfo({ note });
await log.save();
res.send(log);
})
And this is API to retrieve logs of user
app.get('/:id', async (req, res) => {
const { id } = req.params;
// Retrieve model which contain info documents of user with id
const UserInfo = mongoose.model('User_' + id, UserInfoSchema);
const logs = await UserInfo.find();
res.send(logs);
})
I've tested this code and it's working. Each user has a collection to store his data info.
You can download and check it on your local with code at gist https://gist.github.com/huynhsamha/4dcf00a1fba96ae7f186b606b33b7e9c.