正在使用的同一個文件中調用另一個類的方法？

Question

class.mysql.php有2類：MySQL和MySQLResult

class.mysql.php：

<?php 

/** 
* MySQL Database Connection Class 
* @access public 
*/ 
class MySQL { 

    /** 
    * MySQL server hostname 
    * @access private 
    * @var string 
    */ 
    var $host; 
    /** 
    * MySQL username 
    * @access private 
    * @var string 
    */ 
    var $dbUser; 
    /** 
    * MySQL user's password 
    * @access private 
    * @var string 
    */ 
    var $dbPass; 
    /** 
    * Name of database to use 
    * @access private 
    * @var string 
    */ 
    var $dbName; 
    /** 
    * MySQL Resource link identifier stored here 
    * @access private 
    * @var string 
    */ 
    var $dbConn; 
    /** 
    * Stores error messages for connection errors 
    * @access private 
    * @var string 
    */ 
    var $connectError; 

    /** 
    * MySQL constructor 
    * @param string host (MySQL Server hostname) 
    * @param string dbUser (MySQL User Name) 
    * @param string dbPass (MySQL User Password) 
    * @param string dbName (Database to select) 
    * @access public 
    */ 
    function MySQL($host, $dbUser, $dbPass, $dbName) { 
     $this->host = $host; 
     $this->dbUser = $dbUser; 
     $this->dbPass = $dbPass; 
     $this->dbName = $dbName; 
     $this->connectToDb(); 
    } 

    /** 
    * Establishes connection to MySQL and selects a database 
    * @return void 
    * @access private 
    */ 
    function connectToDb() { 
     //Make connection to MySQL server 
     if (!$this->dbConn = @mysql_connect($this->host, $this->dbUser, $this->dbPass)) { 
      trigger_error('Could not connect to server'); 
      $this->connectError = true; 
      //Select database 
     } else if (!mysql_select_db($this->dbName, $this->dbConn)) { 
      trigger_error('Could not select database'); 
      $this->connectError = true; 
     } 
    } 

    /** 
    * Checks for MySQL errors 
    * @return boolean 
    * @access public 
    */ 
    function isError() { 
     if ($this->connectError) { 
      return true; 
     } 
     $error = mysql_error($this->dbConn); 
     if (empty($error)) { 
      return false; 
     } else { 
      return true; 
     } 
    } 

    /** 
    * Returns an instance of MySQLResult to fetch rows with 
    * @param $sql string the database query to run 
    * @return MySQLResult 
    * @access public 
    */ 
    function query($sql) { 
     if (!$queryResource = mysql_query($sql, $this->dbConn)) { 
      trigger_error('Query failed: ' . mysql_error($this->dbConn) . ' SQL: ' . $sql); 
     } 
     return new MySQLResult($this, $queryResource); 
    } 

} 

/** 
* MySQLResult Data Fetching Class 
* @access public 
*/ 
class MySQLResult { 

    /** 
    * Instance of MySQL providing database connection 
    * @access private 
    * @var MySQL 
    */ 
    var $mysql; 
    /** 
    * Query resource 
    * @access private 
    * @var resource 
    */ 
    var $query; 

    /** 
    * MySQLResult constructor 
    * @param object mysql (instance of MySQL class) 
    * @param resource query (MySQL query resource) 
    * @access public 
    */ 
    function MySQLResult(&$mysql, $query) { 
     $this->mysql = &$mysql; 
     $this->query = $query; 
    } 

    /** 
    * Fetches a row from the result 
    * @return array 
    * @access public 
    */ 
    function fetch() { 
     if ($row = mysql_fetch_array($this->query, MYSQL_ASSOC)) { 
      return $row; 
     } else if ($this->size() > 0) { 
      mysql_data_seek($this->query, 0); 
      return false; 
     } else { 
      return false; 
     } 
    } 

    /** 
    * Checks for MySQL Errors 
    * @return boolean 
    * @access public 
    */ 
    function isError() { 
     return $this->mysql->isError(); 
    } 

    /** 
    * Returns the number of rows selected 
    * @return int 
    * @access public 
    */ 
    function size() { 
     return mysql_num_rows($this->query); 
    } 

    /** 
    * Returns the ID of the last row inserted 
    * @return int 
    * @access public 
    */ 
    function insertID() { 
     return mysql_insert_id($this->mysql->dbConn); 
    } 

} 

login.php從form被submitted後檢查username和password。如果字段爲not emptycheck database爲條目。如果有條目，則設置會話。

的login.php：

<?php 
//MySQL class 
require_once('database/class.mysql.php'); 

//Session class 
require_once('session/class.session.php'); 

//Instantiate the mysql class 
require_once('database/dbconnect.php'); 
$db = new MySQL($host, $dbUser, $dbPass, $dbName); 

//Instantiate the Session class 
$session = new Session(); 

//$session->destroy(); 
if (!$session->get('username')) { 
    if (isset($_POST['submit'])) { 
     $username = $_POST['username']; 
     $password = $_POST['password']; 

     if (!empty($username) && !empty($password)) { 
      $sql = "SELECT * FROM user WHERE username = '$username' AND password = '$password'"; 
      $db->query($sql); 
      if ($db->size() == 1) { 
       $session->set('username', $username); 
      } 
     } 
    } 
} 

if (!$session->get('username')) { 
    echo 'not set'; 
} 
?> 
<html> 
    <head> 
    </head> 
    <body> 


     <form method="post" action=""> 
      Username: <input type="text" name="username" /><br /> 
      Password: <input type="text" name="password" /><br /> 
      <input type="submit" name="submit" value="Submit" /> 
     </form> 

    </body> 
</html> 

所以這裏的問題，即時通訊正在使用的login.php此代碼來檢查數據庫條目：

if ($db->size() == 1) 

這段代碼顯然是錯誤的，因爲$db是MySQL class的一個對象，但size() method在MySQLResult class.有沒有簡單的方法可以到size()?在此先感謝

這是我的錯誤：

Fatal error: Call to undefined method MySQL::size() 

Answer 1

$db->query($sql);返回MySQLResult。你必須做一些像

$result = $db->query($sql); 
if ($result->size() == 1) { 

Answer 2

我相信，有一個MySQL classMySQLResult class.和一些其他的類支持數據庫連接

您需要訪問MySQLResult class.的方法，而不包括在登錄頁面

你可以包括MySQLResult class.在MySQL class並創建一個public方法來訪問其功能