Example using Dependency Injection

ExampleDatabase.php

<?php

class ExampleDatabase {

    private $db = null;

    public function __construct($connection_string)
    {
        $this->db = pg_connect($connection_string);
    }

    public function query($query)
    {
        return pg_query($this->db, $query);
    }
}


/* configuration */
$container = new Pimple\Container();
$container['database'] = function() {
    return new ExampleDatabase('dbname=testing');
};

/* usage */
$example_db = $container['database'];
$result = $example_db->query('SELECT * FROM users');