<?php
class MyPDO{
    private $type;      //資料庫類別
    private $host;      //主機地址
    private $port;      //埠號
    private $dbname;    //資料庫名
    private $charset;   //字符集
    private $user;      //使用者名稱
    private $pwd;       //密碼
    private $pdo;       //儲存PDO物件
    private static $instance;
    private function __construct($param) {
        $this->initParam($param);
        $this->initPDO();
        $this->initException();
    }
    private function __clone() {
    }
    public static function getInstance($param=array()){
        if(!self::$instance instanceof self)
            self::$instance=new self($param);
        return self::$instance;
    }
    //初始化引數
    private function initParam($param){
        $this->type=$param['type']??'mysql';
        $this->host=$param['host']??'127.0.0.1';
        $this->port=$param['port']??'3306';
        $this->dbname=$param['dbname']??'sel';
        $this->charset=$param['charset']??'utf8';
        $this->user=$param['user']??'root';
        $this->pwd=$param['pwd']??'';
    }
    //初始化PDO
    private function initPDO(){
        try{
            $dsn="{$this->type}:host={$this->host};port={$this->port};dbname={$this->dbname};charset={$this->charset}";
            $this->pdo=new PDO($dsn, $this->user, $this->pwd);
        } catch (PDOException $ex) {
            $this->showException($ex);
            exit;
        }
    }
    
    //顯示異常
    private function showException($ex,$sql=''){
        if($sql!=''){
            echo 'SQL語句執行失敗<br>';
            echo '錯誤的SQL語句是：'.$sql,'<br>';
        }
        echo '錯誤編號：'.$ex->getCode(),'<br>';
        echo '錯誤行號：'.$ex->getLine(),'<br>';
        echo '錯誤檔案：'.$ex->getFile(),'<br>';
        echo '錯誤資訊：'.$ex->getMessage(),'<br>';
    }
    //設定異常模式
    private function initException(){
        $this->pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
    }

    //執行增、刪、改操作
    public function exec($sql){
        try{
            return $this->pdo->exec($sql);
        } catch (PDOException $ex) {
            $this->showException($ex, $sql);
            exit;
        }
    }
    //獲取自動增長的編號
    public function lastInsertId(){
        return $this->pdo->lastInsertId();
    }

    //判斷匹配的型別
    private function fetchType($type){
        switch ($type){
            case 'num':
                return PDO::FETCH_NUM;
            case 'both':
                return PDO::FETCH_BOTH;
            case 'obj':
                return PDO::FETCH_OBJ;
            default:
                 return PDO::FETCH_ASSOC;
        }
    }
    //獲取所有資料 ，返回二維陣列
    public function fetchAll($sql,$type='assoc'){
        try{
            $stmt=$this->pdo->query($sql);  //獲取PDOStatement物件
            $type= $this->fetchType($type); //獲取匹配方法
            return $stmt->fetchAll($type);
        } catch (Exception $ex) {
            $this->showException($ex, $sql);
        }
    }
    //獲取一維陣列
    public function fetchRow($sql,$type='assoc'){
        try{
            $stmt=$this->pdo->query($sql);  //獲取PDOStatement物件
            $type= $this->fetchType($type); //獲取匹配方法
            return $stmt->fetch($type);
        } catch (Exception $ex) {
            $this->showException($ex, $sql);
            exit;
        }
    }
    //返回一行一列
    public function fetchColumn($sql){
        try{
             $stmt=$this->pdo->query($sql);
            return $stmt->fetchColumn();
        } catch (Exception $ex) {
            $this->showException($ex, $sql);
            exit;
        }
    }
}

//測試
$param=array(
   
);
$mypdo= MyPDO::getInstance($param);

if($mypdo->exec("insert into news values (null,'11','1111',unix_timestamp())"))
    echo '自動增長的編號是：'.$mypdo->lastInsertId ();

$list=$mypdo->fetchColumn('select count(*) from news');
var_dump($list);
?>