Using Mongoose with Node.js

1. Introduction

Mongoose is an ODM (Object Data Modeling) library for MongoDB and Node.js. It provides a straightforward way to model your application data and includes built-in type casting, validation, query building, and business logic hooks.

2. Installation

To install Mongoose, you need Node.js and npm installed. Run the following command in your terminal:

npm install mongoose

3. Basic Usage

To use Mongoose, you first need to connect to your MongoDB database:

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/mydatabase', {
    useNewUrlParser: true,
    useUnifiedTopology: true
}).then(() => {
    console.log('Database connected successfully');
}).catch(err => {
    console.error('Database connection error:', err);
});

4. Schema Definitions

Define the structure of your documents using schemas. Here’s an example of a simple User schema:

const userSchema = new mongoose.Schema({
    name: { type: String, required: true },
    email: { type: String, required: true, unique: true },
    password: { type: String, required: true },
    createdAt: { type: Date, default: Date.now }
});

5. Model Operations

Once you have a schema, you can create a model:

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

Now you can perform various CRUD operations using the model. Below are examples of Create, Read, Update, and Delete operations:

// Create
const newUser = new User({ name: 'John Doe', email: 'john@example.com', password: 'securepassword' });
newUser.save().then(() => console.log('User created'));

// Read
User.find().then(users => console.log(users));

// Update
User.updateOne({ name: 'John Doe' }, { email: 'john.doe@example.com' }).then(() => console.log('User updated'));

// Delete
User.deleteOne({ name: 'John Doe' }).then(() => console.log('User deleted'));

6. Best Practices

Here are some best practices when using Mongoose:

Use schemas to enforce data structure.
Always handle errors in your database operations.
Use indexes for frequently queried fields to improve performance.
Keep your models organized in separate files.

7. FAQ

What is Mongoose?

Mongoose is a Node.js library that provides a schema-based solution to model application data with MongoDB.

How do I connect to MongoDB using Mongoose?

You can connect to MongoDB by using the mongoose.connect() method with the appropriate connection string.

Can I define custom validation in Mongoose?

Yes, Mongoose allows you to define custom validation functions directly in your schema definitions.