OOP PHP错误时，从数据库中获得

Question

我试图让OOP类来获取用户信息用户的信息，但我得到这个错误

致命错误：调用一个成员函数做准备（ ）中的functions.php非对象上

user.php的 - >

include_once 'functions.php'; 
$user = new User(); 

echo $user->get_fullname(5); 

的functions.php - >

include_once 'database.php'; 
class User 
{ 
    public function connect() 
    { 
     $dbh = new DB_Class(); 
    } 

    public function get_fullname($uid) 
    { 

     $getName = $dbh->prepare("SELECT EmailAddress FROM users WHERE UserID =:username"); 
     $getName->bindParam(':username', $uid); 
     $getName->execute(); 
     $rowName = $getName->fetch(); 
     $email = $rowName['emailaddress']; 
     return $email; 

    }  
} 

database.php文件 - >

class DB_Class 
{ 
    public function connect() { 
     try { 
      $dbh= new PDO("mysql:host=localhost;dbname=root",'users','password', array(
       PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, 
       PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8" 
      )); 
     } catch (PDOException $e) { 
      echo $e->getMessage(); 
     } 

     $dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_WARNING); 
     $dbh->setAttribute(PDO::ATTR_CASE,PDO::CASE_LOWER); 
    } 

} 

我在做什么错:(

Answer 1

你从来没有真正赋予访问PDO 。例如$dbh的东西youre设法在使用它，它使用了类好像您选择简单的功能分组，但也期待一些魔术发生:-)这就是我如何与您的existingcode做到这一点：

class DB_Class { 

    protected $dsn; 
    protected $user; 
    protected $password; 

    protected $connection; 

    public function __construct($dsn = null, $user = null, $password = null) 
    { 
     $this->dsn = $dsn; 
     $this->user = $user; 
     $this->password = $password; 
    } 

    public function connect() 
    { 
     if($this->connection) { 
     return $this->connection; 
     } 

     try { 
     $this->connection = new PDO($this->dsn,$this->user, $this->password, 
      array(
       PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, 
       PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8" 
     )); 

     $this->connection->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_WARNING); 
     $this->connection->setAttribute(PDO::ATTR_CASE,PDO::CASE_LOWER); 

     return $this->connection; 
     } 
     catch (PDOException $e) { 

      return false; 
     } 

    } 
} 

class User { 
    protected $db; 

    public function __construct(DB_Class $db = null) 
    { 
     $this->db = $db; 
    } 

    public function setDb(DB_Class $db) 
    { 
     $this->db = $db; 
    } 



    public function get_fullname($uid) 
    { 
     $stmt = $this->db->connect()->prepare("SELECT EmailAddress FROM users WHERE UserID =:username"); 
     $stmt->execute(array(':username', $uid)); 
     if($row = $getName->fetch()) { 
      return $row['emailaddress']; 
     } else { 
      return null; 
     } 
    } 

} 

Answer 2

的$dbh变量没有被传递到get_fullname功能。你需要做这样的事情：

public function connect() 
{ 
    $dbh = new DB_Class(); 
    return $dbh; 
} 

public function get_fullname($uid) 
{ 
    $dbh = $this->connect(); 

Answer 3

需要声明$胸径为通过$ User类的属性和访问这个标识符：

class User 
    { 
protected $dbh; 
    public function connect() 
    { 
    $this->dbh = new DB_Class(); 
    } 

    public function get_fullname($uid) 
    { 

$getName =$this->dbh->prepare("SELECT EmailAddress FROM users WHERE UserID =:username"); 
$getName->bindParam(':username', $uid); 
$getName->execute(); 
$rowName = $getName->fetch(); 
    $email = $rowMail['emailaddress']; 
    return $email; 

    } 

    } 

Answer 4

你从来没有真正赋予你的类属性的属性，声明你的方法中的变量时，将它们放入方法电流范围内的所有你正在做的，一旦方法执行结束后，他们被摧毁。

要正确设置类中的属性，您需要使用$this->varname来声明它们，访问它们也是一样。

您同时还使用了不正确的名称类建筑，构造函数必须设置为__construct不connect。

正如你可以在更新的代码中看到现在$dbh变量是用户类的属性，并可以将它的方法之间调用。

用户类别

class User 
{ 
    public function __construct() 
    { 
     $this->dbh = new DB_Class(); 
    } 

    public function get_fullname($uid) 
    { 

     $getName = $this->dbh->getConnection()->prepare("SELECT EmailAddress FROM users WHERE UserID =:username"); 
     $getName->bindParam(':username', $uid); 
     $getName->execute(); 
     $rowName = $getName->fetch(); 
     $email = $rowName['emailaddress']; 
     return $email; 

    }  
} 

数据库类

class DB_Class 
{ 
    public function __construct() { 
     try { 
      $this->dbh = new PDO("mysql:host=localhost;dbname=root",'users','password', array(
       PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, 
       PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8" 
      )); 
     } catch (PDOException $e) { 
      echo $e->getMessage(); 
     } 

     $this->dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_WARNING); 
     $this->dbh->setAttribute(PDO::ATTR_CASE,PDO::CASE_LOWER); 
    } 

    public function getConnection() { 
     return $this->dbh; 
    } 
} 

您将使用http://us2.php.net/manual/en/oop5.intro.php作为资源大大受益。