public function __construct()
{
    try
    {
        #array com dados do banco
        include 'database.conf.php';
        global $databases;
        $this->config = $databases['local'];
        # Recupera os dados de conexao do config
        $this->dbname = $this->config['dbname'];
        $this->host = $this->config['host'];
        $this->port = $this->config['port'];
        $this->user = $this->config['user'];
        $this->pass = $this->config['password'];
        # instancia e retorna objeto
        $this->con = @mysql_connect( "$this->host", "$this->user", "$this->pass" );
        @mysql_select_db( "$this->dbname" );
        if ( !$this->con )
        {
            throw new Exception( "Falha na conexão MySql com o banco [$this->dbname] em database.conf.php" );
        }
        else
        {
            return $this->con;
        }
    }
    catch ( Exception $e )
    {
        echo $e->getMessage();
        exit;
    }
    return $this;
}

<?php
global $databases;
$databases = array(
    'local' => array
    (
            'host'=>'localhost',
            'port'=>3306,
            'dbname'=>'ok',
            'user'=>'root',
            'password'=>'root'
    )
);