msqli

<?php
    defined('DB_SERVER') ? null : define("DB_SERVER", "localhost");
    defined('DB_USER')   ? null : define("DB_USER", "root");
    defined('DB_PASS')   ? null : define("DB_PASS", "*************");
    defined('DB_NAME')   ? null : define("DB_NAME", "*************");
?>

<?php

class database extends mysqli {

    private $db;

    function __construct() {
        $this->db = new mysqli(DB_SERVER, DB_USER, DB_PASS, DB_NAME);

        if ($this->db->connect_errno > 0) {
            die("Unable to connect to the database, throwing error: " . $db->connect_error);
        }
    }

    // performs a query, does a number of actions dependant on $type
    public function query($sql, $type = false) {
        $sql = $this->escape($sql);

        if ($result = $this->db->query($sql)) {
            if ($type == false) {
                return $result;
            } elseif ($type == true || "assoc") {
                if ($result->num_rows >= 2) {
                    $array;
                    $i = 1;

                    while ($row = $result->fetch_assoc()) {
                        $array[$i] = $row;
                        $i++;
                    }

                    return $array;
                } elseif ($result->num_rows == 1) {
                    return $result->fetch_assoc();
                }
            } elseif ($type == "array") {
                if ($result->num_rows >= 2) {
                    $array;
                    $i = 1;

                    while ($row = $result->fetch_array()) {
                        $array[$i] = $row;
                        $i++;
                    }

                    return $array;
                } elseif ($result->num_rows == 1) {
                    return $result->fetch_array();
                }
            }
        } else {
            die("There was an error running the query, throwing error: " . $this->db->error);
        }
    }

    // escapes a string before it is used in a query
    private function escape($string) {
        $string = $this->db->escape_string($string);
        return $string;
    }

}

$db = new database();

?>