Connecting with PHP

This guide explains how to establish a connection between a PHP application and a PostgreSQL database using the built-in PDO extension. It walks through the necessary setup, configuration, and execution of a simple SQL query.

Variables

To connect to a PostgreSQL database, you only need one environment variable — the connection URI. This URI contains all the necessary information like username, password, host, port, and database name.

The URI will look like this:

postgresql://<USER>:<PASSWORD>@<HOST>:<PORT>/<DATABASE>

You can find the details needed in the URI from the Elestio service overview details. Copy and replace the variables carefully in the URI example provided above.

Prerequisites

Install PHP

Check if PHP is installed by running:

php -v

If not installed, download and install it from https://www.php.net/downloads.php.

Code

Once all prerequisites are set up, create a new file named pg.php and add the following code and replace the POSTGRESQL_URI with actual link or in environment setup as you wish:

<?php

$db_url = "POSTGRESQL_URI";//Replace with actual URI
$db_parts = parse_url($db_url);

$dsn = "pgsql:host={$db_parts['host']};port={$db_parts['port']};dbname=Elestio";//Replace with your DB name
$pdo = new PDO($dsn, $db_parts['user'], $db_parts['pass']);

$version = $pdo->query("SELECT VERSION()")->fetchColumn();
echo $version;

To execute the script, open the terminal or command prompt and navigate to the directory where pg.php. Once in the correct directory, run the script with the command

php pg.php

If the connection is successful, the terminal will display output similar to:

PostgreSQL 16.8 (Debian 16.8-1.pgdg120+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit