OOP PHP + PDO - 应该是这样吗？

Question

在我开始在我的项目中实施以下内容之前，我正在尝试创建一个简单的示例类，我想知道是否有一些我可以/应该改进的地方。如果有人给我一些关于我现在做得如何的意见，我会很高兴。

简单的类示例：

  // define class
  class User{
  private $UserID;
  private $UserName;
  private $Email;

  function SetUserID($NewUserID){
    $this -> UserID = $NewUserID;
    }

  function GetUserID(){
    return $this -> UserID;
    }

  function SetUserName($NewUserName){
    // update object
    $this -> UserName = $NewUserName;
    } 

  function GetUserName(){
    return $this -> UserName;
    }

  function SetEmail($NewEmail){
    $this -> Email = $NewEmail;          
    } 

  function GetEmail(){
    return $this -> Email;
    }

  public function SaveUser(){
    // check if user exists
    $User = new User();
    if ($User->UserExists($this->UserID)){
      // user exists - update him
      $Pdo = new PDO('mysql:host=localhost;dbname=cms;charset=utf8', 'xxx', 'xxx');  
      $Query = $Pdo->prepare("Update User set UserName = :UserName, Email = :Email, UserID = :UserID where UserID = :UserID");
      $Query->bindValue(':UserName', $this->UserName);
      $Query->bindValue(':Email', $this->Email);
      $Query->bindValue('UserID', $this->UserID);
      $Query->execute();
      $Pro = null;
      }
    else{
      // insert new
      $Pdo = new PDO('mysql:host=localhost;dbname=cms;charset=utf8', 'xxx', 'xxx');  
      $Query = $Pdo->prepare("Insert into User (UserName, Email) values (:UserName, :Email)");
      $Query->bindValue(':UserName', $this->UserName);
      $Query->bindValue(':Email', $this->Email);
      $Query->execute();
      // close connection
      $Pdo = null; 
      }
    }

  private function UserExists($UserID){
    // returns true if users exists, false if not
    $Pdo = new PDO('mysql:host=localhost;dbname=cms;charset=utf8', 'root', 'vertrigo');
    $Query = $Pdo->prepare("SELECT * FROM User WHERE UserID=:UserID"); 
    $Query->bindValue(':UserID', $UserID);
    $Query->execute();
    $Row = $Query->fetch(PDO::FETCH_ASSOC);
    $Pdo = null;

    // get user
    if ($Row){
      return true;
      }
    else{
      return false;
      }
    }        
  }

function GetUserInfo($UserID){
  // open pdo
  $Pdo = new PDO('mysql:host=localhost;dbname=cms;charset=utf8', 'root', 'vertrigo');  
  $Query = $Pdo->prepare("SELECT * FROM User WHERE UserID=:UserID");
  $Query->bindValue(':UserID', $UserID);
  $Query->execute();
  $Row = $Query->fetch(PDO::FETCH_ASSOC);
  $Pdo = null;

  // get UserInfo
  $UserInfo = new User();
  $UserInfo -> SetUserID($UserID);
  $UserInfo -> SetUserName($Row["UserName"]); 
  $UserInfo -> SetEmail($Row["Email"]); 

  // return UserInfo
  return $UserInfo;
  }

这只是我想如何使用它的一个基本示例。你觉得我应该改进什么？

Answer 1

任何 PHP 应用程序只需一次连接到数据库。
因此，您的班级必须使用已创建的连接，而不是每次都创建它。

class User{
  private $UserID;
  private $UserName;
  private $Email;
  private $db;

  function __construct($pdo) {
    $this->db = $pdo;
  }

  private function UserExists($UserID)
  {
    $sql = "SELECT 1 FROM User WHERE UserID=?";
    $stm = $this->db->prepare($sql);
    $stm->execute(array($UserID));
    return $stm->fetchColumn();
    }        
  }
  // the rest going to use the same approach
}

$pdo = //see PDO tag wiki for theproper  example

$user = new User($pdo);
if ($user->UserExists($UserID)) {
  // whatever
}