How to fetch data from postgresql using d3.js?

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by addison , in category: Javascript , a month ago

How to fetch data from postgresql using d3.js?

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1 answer

by giovanny.lueilwitz , a month ago

@addison 

To fetch data from PostgreSQL using d3.js, you can make an AJAX request to your server-side application that will query the database and return the data in a format that d3.js can work with. Here is a basic example using Node.js and Express as the server-side application:

  1. Install the necessary npm packages:
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npm install express pg


  1. Create a server-side application using Node.js and Express:
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const express = require('express');
const { Pool } = require('pg');
const app = express();

const pool = new Pool({
  user: 'your_username',
  host: 'localhost',
  database: 'your_database',
  password: 'your_password',
  port: 5432,
});

app.get('/data', (req, res) => {
  pool.query('SELECT * FROM your_table', (err, result) => {
    if (err) {
      console.error(err);
      res.status(500).send('Error fetching data');
    } else {
      res.json(result.rows);
    }
  });
});

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


  1. Create an HTML file with d3.js to fetch and display the data:
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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Fetch data from PostgreSQL using d3.js</title>
  <script src="https://d3js.org/d3.v6.min.js"></script>
</head>
<body>
  <script>
    d3.json('http://localhost:3000/data')
      .then(data => {
        console.log(data); // Data fetched from PostgreSQL
        // Use d3.js to visualize the data
      })
      .catch(error => console.error('Error fetching data:', error));
  </script>
</body>
</html>


  1. Run your server-side application:
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node server.js


  1. Open your HTML file in a browser to see the data fetched from PostgreSQL and visualize it using d3.js.


This is a simple example to get you started. Depending on your project requirements, you may need to customize the server-side application and the d3.js code to suit your needs.