db.class.php

<?php

    class DB {

            private static $instance;
            private static $con;
            private static $customError;

            public static function init($host, $user, $pass, $db) {

                if(!isset(self::$instance)) {

                    try {
                        self::$instance = new PDO('mysql:host='.$host.';dbname='.$db, $user, $pass);
                        self::$instance->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                        self::$con = true;
                    }
                    catch (PDOException $e) {

                        self::$customError = $e->getMessage();
                        self::$con = false;
                    }
                }
            }

            public static function isConnected() {

                return self::$con;
            }

            public static function query($query, $params = array()) {

                try {
                    $params = !is_array($params) ? array($params) : $params;
                    $data = array();
                    $is_select = strtoupper(substr($query,0,6)) == "SELECT" ? true : false;

                    if(count($params) > 0) {

                        $stmt = self::$instance->prepare($query);

                        if(!$stmt)
                        {
                            return false;
                        }

                        $stmt->execute($params);

                        if($is_select)
                            $data = $stmt->fetchAll(PDO::FETCH_ASSOC);
                        else {
                            $data = true;
                        }

                        $stmt->closeCursor();
                    }
                    else {

                        $res = self::$instance->query($query);

                        if(!$res)
                        {
                            return false;
                        }
                        else if($is_select)
                        {
                            foreach($res as $row)
                                $data[] = $row;
                        }
                        else
                        {
                            $data = true;
                        }
                    }

                    self::$customError = "";

                    return $data;
                }
                catch(Exception $e) {

                    self::setError($e->getMessage());
                    return false;
                }
            }

            public static function getError() {

                if(strlen(self::$customError) > 0)
                {
                    return self::$customError;
                }
                else
                {
                    $err = self::$instance->errorInfo();
                    return $err[count($err)-1];
                }
            }

            public static function setError($e) {

                self::$customError = $e;
            }
        }