How Can You Effectively Connect Node.js to a Database Using Sequelize ORM?

Connecting Frontend (EJS) with Node.js

Node.js acts as a bridge between the frontend (EJS) and the backend, enabling data to be stored in the database. This setup allows for dynamic content generation and seamless data handling through server-side scripts.

Database Types and ORMs

Understanding database types is crucial when working with Node.js. Databases are categorized into two main types:

SQL (Structured Query Language): Relational databases like MySQL, PostgreSQL, and Oracle. They are used for structured data and do not support arrays.
NoSQL (Not Only SQL): Non-relational databases such as MongoDB, Cassandra, and Redis. These databases are more flexible, supporting various data types like images and videos, and are scalable for frequent updates.

SQL Commands and ORM

Raw SQL commands, while powerful, are prone to SQL injection attacks. For example:

INSERT INTO hello (name, address) VALUES ('Sudip Sharma', 'Pokhara');

To enhance security, ORMs (Object-Relational Mapping) are used. ORMs abstract raw SQL commands into object-oriented methods. For example:

Hello.create({ name: 'Sudip Sharma', address: 'Pokhara' });

ORMs in Node.js include Sequelize, Mongoose, and Prisma, providing methods like `find()`, `create()`, `update()`, and `delete()` that internally translate to raw SQL commands.

Benefits of ORM

ORMs simplify database operations compared to writing raw SQL queries.
They improve security by preventing SQL injection attacks.
Learning one ORM (e.g., Sequelize) can apply to multiple database systems, reducing the need to learn different SQL dialects for each database.

Database Management Tools

For managing different types of databases, use the following tools:

PostgreSQL: pgAdmin
SQL Server: SQL Server Management Studio
MySQL: MySQL Workbench (useful if XAMPP crashes)

CRUD Operations with XAMPP

To perform CRUD operations using Sequelize with MySQL2, install the necessary packages using npm:

npm install sequelize
npm install mysql2

Verify the installation in your `package.json` file to ensure everything is set up correctly.

Example Code and Sequelize Configuration

Here’s an example of how to configure Sequelize for a MySQL database:

const { Sequelize, DataTypes } = require('sequelize');
const sequelize = new Sequelize('sudip', 'root', '', {
host: 'localhost',
port: 3306,
dialect: 'mysql'
});

sequelize.authenticate().then(() => {
console.log('Connection has been established successfully.');
}).catch(err => {
console.error('Unable to connect to the database:', err);
});

sequelize.sync({ force: false }).then(() => {
console.log('Database is migrated and synchronized successfully.');
});

In this example:

The `Sequelize` instance is created with database credentials and configuration options.
The `authenticate()` method is used to check if the connection to the database is successful.
The `sync()` method updates the database schema according to the models defined.