To integrate a database with EJS in a Node.js Express application, you’ll need to go through a few fundamental steps. Below is a detailed guide that will help you set up your environment and successfully connect a database to your Node.js Express application, while using EJS for rendering views.

Step 1: Set Up the Express Application

Start by creating a new directory for your project and initializing it with npm:

bash
mkdir myapp
cd myapp
npm init -y

Install the required dependencies:

bash
npm install express ejs

Step 2: Choose and Install a Database

For simplicity, let’s assume you are using a MongoDB database with Mongoose as the ODM (Object Data Modeling) library. Install mongoose:

bash
npm install mongoose

If you’re using another database like MySQL or PostgreSQL, you’d install corresponding packages like mysql2 or pg.

Step 3: Create the Basic App Structure

Create an Express application with EJS as the view engine:

javascript
// app.js
const express = require(‘express’);
const mongoose = require(‘mongoose’);
const app = express();

// Set ‘views’ directory and ‘ejs’ as the view engine
app.set(‘views’, ‘./views’);
app.set(‘view engine’, ‘ejs’);

// Connect to MongoDB
mongoose.connect(‘mongodb://localhost:27017/mydatabase’, {
useNewUrlParser: true,
useUnifiedTopology: true,
});

// Define a basic route
app.get(‘/’, (req, res) => {
res.render(‘index’, { title: ‘My App’, message: ‘Hello, World!’ });
});

// Start the server
app.listen(3000, () => {
console.log(‘Server is running on http://localhost:3000’);
});

Step 4: Create a Mongoose Model

Say you want to add a model for storing users:

javascript
// models/User.js
const mongoose = require(‘mongoose’);

const userSchema = new mongoose.Schema({
name: String,
email: String,
});

const User = mongoose.model(‘User’, userSchema);

module.exports = User;

Step 5: Interact with the Database and Render Data

Create a route that interacts with your database:

javascript
// Continue in app.js or create a new routes file

const User = require(‘./models/User’);

// Define a route that fetches users from the database
app.get(‘/users’, async (req, res) => {
const users = await User.find();
res.render(‘users’, { title: ‘User List’, users: users });
});

Step 6: Create EJS Templates

Create EJS templates in the views directory.

views/index.ejs

html

<%= message %>

views/users.ejs

html

User List

<% users.forEach(user => { %>
• <%= user.name %> (<%= user.email %>)

<% }) %>

Step 7: Test Your Application

Run your application using Node.js:

bash
node app.js

Visit http://localhost:3000/ to see the EJS rendered homepage, and http://localhost:3000/users to see the list of users fetched from the database.

Conclusion

By following these steps, you set up an Express application using EJS for views and connected it to a MongoDB database using Mongoose. For other databases, such as MySQL or PostgreSQL, you would replace Mongoose with the relevant database driver or ORM, and the query methods would differ accordingly.