Using Mongoose for Database Operations

Tutorial 2 of 5

1. Introduction

1.1. Brief Explanation of the Tutorial's Goal

This tutorial will guide you on how to use Mongoose for interacting with your MongoDB database. Mongoose is an elegant MongoDB object modeling for Node.js that provides a straightforward, schema-based solution to model your application data.

1.2. What the User will Learn

By the end of this tutorial, you'll learn:

  • How to setup and connect Mongoose to MongoDB.
  • Basic Mongoose operations like creating, reading, updating, and deleting data (CRUD operations).

1.3. Prerequisites

  • Basic knowledge of JavaScript and Node.js.
  • MongoDB installed on your local system.
  • Node.js and npm (Node package manager) installed on your local system.

2. Step-by-Step Guide

2.1. Setting up Mongoose

Before using Mongoose, you have to install it via npm.

npm install mongoose

Then, you can import and use it in your Node.js file as shown below:

const mongoose = require('mongoose');

2.2. Connecting Mongoose to MongoDB

To connect Mongoose to MongoDB, use the mongoose.connect() function. You'll need to specify your MongoDB URI as one of the parameters.

mongoose.connect('mongodb://localhost/my_database', {useNewUrlParser: true, useUnifiedTopology: true});

The useNewUrlParser and useUnifiedTopology options are to handle MongoDB driver deprecation warnings.

2.3. Defining a Model

A Mongoose model is a blueprint for creating documents within a MongoDB collection. It is defined using the mongoose.model() function which takes two arguments: the singular name of the collection your model is for and the schema of your model.

const Schema = mongoose.Schema;

const UserSchema = new Schema({
  name: String,
  email: String,
  password: String
});

const User = mongoose.model('User', UserSchema);

3. Code Examples

3.1. Creating Documents

To create documents in MongoDB using Mongoose, you can use the save() method.

const newUser = new User({
  name: 'John Doe',
  email: 'john@example.com',
  password: 'password123'
});

newUser.save((error, document) => {
  if (error) console.log(error);
  console.log(document);
});

3.2. Reading Documents

Use the find() method to read documents from your MongoDB collection.

User.find({name: 'John Doe'}, (error, documents) => {
  if (error) console.log(error);
  console.log(documents);
});

4. Summary

We have covered how to set up and connect Mongoose to MongoDB, defining a Mongoose model, and performing basic CRUD operations. For further learning, explore Mongoose validation, middleware, and complex queries.

5. Practice Exercises

Exercise 1: Create a new Mongoose model for a Product with name, price, and category fields.

Exercise 2: Write a function to update the price of a Product.

Exercise 3: Write a function to delete a Product from the database.

Solutions:

  1. Refer to the section on defining a model.
  2. Use the updateOne() or updateMany() functions.
  3. Use the deleteOne() or deleteMany() functions.

Remember, practice makes perfect. Keep trying different operations and exploring the Mongoose documentation for more in-depth knowledge.