Connecting Multiple Database in NodeJs with MongoDB and Mongoose

readme.txt

Connecting Multiple Database in NodeJs with MongoDB and Mongoose.

Mongoose doesn't allow to use multiple databases in single mongoose instance as the models are build on one connection.

While using multiple mongoose instances, Node.js will not allow multiple module instances as it has caching system in require(). 
we've tried to use createConnection() and openSet() in mongoose, but it was not the solution. So we create all from start to finish.

Here you can get the solution

Explanation file: model.js
The following code defines the data models to be used with each of the databases by associating them with a
previously defined schema (userSchema and qrSchema).  
Data models are exported for use elsewhere in the code.

Connecting Multiple Database in NodeJs with MongoDB and Mongoose

Explanation file: db.js
This code imports the mongoose library which allows to connect to a MongoDB database. 
There are two URIs defined to connect to two different databases: MONGO_URI and MOBILE_URI.  
Each URI contains connection information to a remote MongoDB database, including user credentials.

 The connectDBs function uses the mongoose.createConnection method to create connections to these two 
 databases using the respective URIs.  The useUnifiedTopology and useNewUrlParser options are set to enable the new 
 unified topology policy and use MongoDB's new URL parser, respectively.

 The function returns an object that contains the connections to these two databases as qrCodeDb and userDB properties.

db.js

const mongoose = require('mongoose')

const MONGO_URI =
    'mongodb+srv://owlhacking:[email protected]/qrCodeData?retryWrites=true&w=majority'
const MOBILE_URI =
    'mongodb+srv://owlhacking:[email protected]/Cluster0?retryWrites=true&w=majority'

const connectDBs = () => {
    try {
        const qrCodeDb = mongoose.createConnection(MONGO_URI, {
            useUnifiedTopology: true,
            useNewUrlParser: true
        })
        const userDB = mongoose.createConnection(MOBILE_URI, {
            useUnifiedTopology: true,
            useNewUrlParser: true
        })
        return { qrCodeDb, userDB }
    } catch (error) {
        console.error(`Error:${error.message}`)
        process.exit(1)
    }
}

module.exports = { connectDBs }

model.js

const { default: mongoose } = require('mongoose')
const { connectDBs } = require('../config/db')

const qrSchema = mongoose.Schema({
    qrInformation: {
        type: String,
        required: true
    },
    qrImage: {
        type: String,
        required: true
    },
    timeStamp: {
        type: String,
        default: Date()
    }
})

const userSchema = new mongoose.Schema({
    fullname: {
        type: String,
        required: true
    },
    email: {
        type: String,
        required: true,
        unique: true
    },
    password: {
        type: String,
        required: true
    }
})
const { qrCodeDb, userDB } = connectDBs()

module.exports = {
    userSchema: userDB.model('user', userSchema),
    Qrcode: qrCodeDb.model('Qrcode', qrSchema)
}

Useful, thanks!

The above trick really work
Thanks :)

Useful, thanks!

You’re welcome😇

The above trick really work Thanks :)

Glad that it has helped you😊

Useful; works, danke.