expressjsHow can I use Express.js and PostgreSQL together to create a web application?

Express.js and PostgreSQL can be used together to create a web application.

Example code

const express = require('express')
const { Client } = require('pg')

const app = express()

const client = new Client({
  user: 'postgres',
  host: 'localhost',
  database: 'my_database',
  password: 'my_password',
  port: 5432,
})

client.connect()

app.get('/', (req, res) => {
  client.query('SELECT * FROM users', (err, result) => {
    if (err) {
      console.log(err.stack)
    } else {
      res.send(result.rows)
    }
  })
})

app.listen(3000, () => {
  console.log('Server listening on port 3000')
})

Output example

Server listening on port 3000

This code creates an Express.js application which connects to a PostgreSQL database and sends a query to the users table. It then sends the result of the query to the client.

Code explanation

1. const express = require('express'): This imports the Express.js module.
2. const { Client } = require('pg'): This imports the PostgreSQL Client module.
3. const app = express(): This creates an Express.js application.
4. const client = new Client({...}): This creates a new PostgreSQL Client instance with the given configuration.
5. client.connect(): This connects to the PostgreSQL database.
6. app.get('/', (req, res) => {...}): This creates a route handler for the root route which sends a query to the users table in the database and sends the result to the client.
7. app.listen(3000, () => {...}): This starts the Express.js application on port 3000.

Helpful links

• Express.js
• PostgreSQL

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