Connecting CodeIgniter 3.0.6 with PostgreSQL

Question

I am trying to connect CodeIgniter 3.0.6 with PostgreSQL, and am using an Apache HTTP server with PHP 7.0.5. I looked for some solution in the forums but I did not find anything about it.

Here is the database configuration:

$db['default'] = array(
    'dsn'   => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => 'password',
    'database' => 'db_name',
    'dbdriver' => 'postgre',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE,
    'port' => 5432
);

The error message is as follows:

An uncaught Exception was encountered

Type: Error

Message: Call to undefined function pg_connect()

Filename: E:\xampp\htdocs\facturacion\system\database\drivers\postgre\postgre_driver.php

Line Number: 155

Image of exception