无法使用PHP脚本连接到本地托管的mysql

I am trying to build a self-hosted PHP site, but I am having trouble connecting to the database from my PHP script.

Please note the following

1). This code allows me to connect to MAMP from my terminus without problem so I know MySQL is working etc

mysql --host=127.0.0.1 --port=8889 --user=root -p 

2) When I tried to build a site on a remote hosted platform, this code allowed me to connect from my php script to MySQL on the remove server, so I know there is nothing wrong with this code per se, but it didn't work on my computer.

defined('DB_SERVER') ? null : define("DB_SERVER","host");
defined('DB_USER') ? null : define("DB_USER","username");
defined('DB_PASS') ? null : define("DB_PASS","password");
defined('DB_NAME') ? null : define("DB_NAME","photo_gallery");

3 I have been able to run a self-hosted wordpress site on my computer, but I didn't establish the database connection for that (it's somewhere in the code) so I don't what I'm doing wrong. That site is accessible at the following path. http://localhost:8888/wordpress/ even though it is connected at port 8889 (according to mysql)

4 MAMP tells me that I can connect to the database from my own scripts using this format

Host    localhost
Port    8889
User    root
Password    root

Therefore, I added this line

defined('DB_PORT') ? null : define("DB_PORT","8889");

to this group, like so

defined('DB_SERVER') ? null : define("DB_SERVER","host");
    **defined('DB_PORT') ? null : define("DB_PORT","8889");**
    defined('DB_USER') ? null : define("DB_USER","username");
    defined('DB_PASS') ? null : define("DB_PASS","password");
    defined('DB_NAME') ? null : define("DB_NAME","photo_gallery");

but it still didn't work. I'm being told database connection fails when I try to test it.

Any ideas?

EDIT. I tried to put the port next to the localhost but it's not working.

defined('DB_SERVER') ? null : define("DB_SERVER","localhost:8889");
defined('DB_USER') ? null : define("DB_USER","root");
defined('DB_PASS') ? null : define("DB_PASS","root");
defined('DB_NAME') ? null : define("DB_NAME","photo_gallery");

EDIT. The above code was in the config.php which was included into the database.php which is this

<?php 

require_once("config.php");

class MySQLDatabase {

    private $connection;

    function __construct(){
        $this->open_connection();
    }

    public function open_connection(){
        $this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS);
    if(!$connection){
        die("Database connection failed:" . mysql_error());
        } else {
        $db_select = mysql_select_db(DB_NAME, $this->connection);
        if (!$db_select) {
            die("Database selection failed: " . mysql_error());
        }
        }
    }

    public function close_connection(){

        if(isset($this->connection)){
            mysql_close($this->connection);
            unset($this->connection);
        }
    }


    public function query($sql) {
    $result = mysql_query($sql, $this->connection);
    $this->confirm_query($result);
        return $result;
    }

    public function mysql_prep( $value ) {
        $magic_quotes_active = get_magic_quotes_gpc();
        $new_enough_php = function_exists( "mysql_real_escape_string" ); // i.e. PHP >= v4.3.0
        if( $new_enough_php ) { // PHP v4.3.0 or higher
            // undo any magic quote effects so mysql_real_escape_string can do the work
            if( $magic_quotes_active ) { $value = stripslashes( $value ); }
            $value = mysql_real_escape_string( $value );
        } else { // before PHP v4.3.0
            // if magic quotes aren't already on then add slashes manually
            if( !$magic_quotes_active ) { $value = addslashes( $value ); }
            // if magic quotes are active, then the slashes already exist
        }
        return $value;
    }

    private function confirm_query($result){
        if(!$result){
            die("Database query failed:" . mysql_error());
        }
    }

}


$database = new MySQLDatabase();


?>