NodeJs

Node.js and PostgreSQL: Building a CRUD Application

Posted on by thuan

Node.js and PostgreSQL are two powerful technologies that can be used together to build full-stack applications. Node.js is a server-side JavaScript runtime, while PostgreSQL is a popular open-source relational database management system. In this article, we’ll explore how to use these two technologies together to build a CRUD (Create, Read, Update, Delete) application.

What is a CRUD application?

A CRUD application is an application that allows users to create, read, update, and delete data. In a typical CRUD application, the data is stored in a database, and the application provides a user interface for users to interact with the data.

Building a CRUD application with Node.js and PostgreSQL

To build a CRUD application with Node.js and PostgreSQL, we’ll need to use Node.js to create a server-side API that interacts with a PostgreSQL database.

Setting up a PostgreSQL database

The first step in building a CRUD application with Node.js and PostgreSQL is to set up a PostgreSQL database. We can use the PostgreSQL command-line interface (CLI) to create a new database and a new table.

For example, we could create a “users” table with the following schema:

sql
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  name TEXT,
  email TEXT UNIQUE,
  password TEXT
);

Creating a Node.js API

Next, we’ll need to create a Node.js API that interacts with our PostgreSQL database. We can use the Node.js pg module to connect to our database and execute SQL queries.

For example, we could create a route that retrieves a list of users from our database:

csharp
const { Pool } = require('pg');
const pool = new Pool();

app.get('/users', async (req, res) => {
  const { rows } = await pool.query('SELECT * FROM users');
  res.send(rows);
});

Creating a CRUD API

To create a full CRUD API, we’ll need to add routes for creating, updating, and deleting data as well. For example, we could create a route that allows users to create a new user:

csharp
app.post('/users', async (req, res) => {
  const { name, email, password } = req.body;
  const { rows } = await pool.query(
    'INSERT INTO users (name, email, password) VALUES ($1, $2, $3) RETURNING *',
    [name, email, password]
  );
  res.send(rows[0]);
});

Creating a client-side application

Finally, we’ll need to create a client-side application that interacts with our Node.js API. We can use any client-side framework or library, such as React or Angular, to build our application.

For example, we could create a React component that retrieves a list of users from our Node.js API:

javascript
import React, { useState, useEffect } from 'react';
import axios from 'axios';

function UserList() {
  const [users, setUsers] = useState([]);

  useEffect(() => {
    axios.get('/users')
      .then(res => setUsers(res.data))
      .catch(err => console.log(err));
  }, []);

  return (
    <ul>
      {users.map(user => (
        <li key={user.id}>{user.name} ({user.email})</li>
      ))}
    </ul>
  );
}

Conclusion

Building a CRUD application with Node.js and PostgreSQL allows us to create a powerful and scalable application that can handle a large amount of data. With Node.js, we can create a flexible and scalable API that interacts with a PostgreSQL database, while the client-side framework or library allows us to create a dynamic and responsive user interface. By combining these technologies, we can build modern and feature-rich applications that meet the needs of today’s users.

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