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Use Mongoose with MongoDB in Ubuntu 19.10

Author: Nabeel Ahmed

Last Updated: Fri, May 8, 2020
MongoDB Programming Ubuntu

Introduction

Mongoose is an ODM (Object Data Modeling) library built on top of the MongoDB driver. It allows for concise interaction with MongoDB and simple object modeling within a NodeJS environment.

Prerequisites

Before starting, it is recommended that you:

1. MongoDB

Install MongoDB.

$ sudo apt install mongodb

Verify it was installed properly. Look for "active (running)" in the output.

$ sudo systemctl status mongodb

Active: active (running)

2. NodeJS and NPM

Add the latest stable NodeJS repository.

$ curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -

Install NodeJS.

$ sudo apt install nodejs

Verify NodeJS and NPM are installed properly.

$ node -v && npm -v

v12.x.x

6.x.x

3. Initialize the Mongoose Project

Create the project root directory.

$ cd ~

$ mkdir mongooseProject && cd mongooseProject

Initialize a NodeJS development environment to automatically generate a package.json:

$ npm init

Answer the short questions to fit your project. For example, if you press return at each question to accept the defaults, the npm init process responds:

About to write to /root/mongooseProject/package.json:



{

"name": "mongooseproject",

"version": "1.0.0",

"description": "",

"main": "index.js",

"scripts": {

    "test": "echo \"Error: no test specified\" && exit 1"

},

"author": "",

"license": "ISC"

}

Install the required packages using npm in the project root directory:

$ npm install --save mongoose

4. Define a Model

Create a folder called Models in the root directory of the project and cd into it:

$ cd ~/mongooseProject

$ mkdir Models && cd Models

Create connectDB.js. This file will contain the connection logic needed for the MongoDB server.

$ nano connectDB.js

Paste the following into connectDB.js.

const mongoose = require('mongoose'); // Import mongoose library



module.exports = function(uri) {

    mongoose.connect(uri, {  //attempt to connect to database

        useNewUrlParser: true, // Recommended, insures support for future MongoDB drivers

        useUnifiedTopology: true // Recommended, uses new MongoDB topology engine

    }).catch(error => console.log(error)) // Error handling





    mongoose.connection.on('connected', function () { // On connection

        console.log('Successful connection with database: ' + uri); // Callback for successful connection

    });

}

Create Users.js. This file will contain the model for the database collection Users.

$ nano Users.js

Paste the following into Users.js. This defines a basic schema for users.

const mongoose = require("mongoose"); // Import mongoose library

const Schema = mongoose.Schema // Define Schema method



// Schema

var UsersSchema = new Schema({ // Create Schema

    name: String, // Name of user

    age: Number, // Age of user

    role: String // Role of user

})



// Model

var Users = mongoose.model("Users", UsersSchema) // Create collection model from schema

module.exports = Users // export model

5. Insert Documents into MongoDB

Create insertUser.js in the root directory of the project.

$ cd ~/mongooseProject

$ nano insertUser.js

Paste the following into insertUser.js file. This file inserts documents into the Users collection.

//Library

const mongoose = require("mongoose")



// Database connection

const connectDB = require("./Models/connectDB")

var database = "mongoose" // Database name



// Models

const Users = require("./Models/Users")



// Connect to database

connectDB("mongodb://localhost:27017/"+database)



var insertedUser = new Users({ // Create new document

    name: "John Doe",

    age: 18,

    role: "Example User"

})



insertedUser.save(err => { // save document inside Users collection

    if(err) throw err // error handling

    console.log("Document inserted!")

    mongoose.disconnect() // disconnect connection from database once document is saved

})

Run insertUser.js.

$ node insertUser.js

Successful connection with database: mongodb://localhost:27017/mongoose

Document inserted!

6. Read Documents from MongoDB

Create readUsers.js in the root directory of the project.

$ cd ~/mongooseProject

$ nano readUsers.js

Paste the following into readUsers.js. This file reads documents in the Users collection.

//Library

const mongoose = require("mongoose")



// Database connection

const connectDB = require("./Models/connectDB")

var database = "mongoose" // Database name



// Models

const Users = require("./Models/Users")



// Connect to database

connectDB("mongodb://localhost:27017/"+database)



Users.find({}, (err, users)=>{ //find and return all documents inside Users collection

    if(err) throw err // error handling

    console.log(users)

    mongoose.disconnect()

})

Run readUsers.js. The output is an array of objects.

$ node readUsers.js

Successful connection with database: mongodb://localhost:27017/mongoose

[ { _id: ************************,

    name: 'John Doe',

    age: 18,

    role: 'Example User',

    __v: 0 } ]

Conclusion

You have set up Mongoose to work with MongoDB. For more information, please see the Mongoose API documentation

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