Question

这是我的班级代码

<?php 

class DatabaseFunctions{

    public $serverName  = SERVER_NAME ;
    public $userName    = USER_NAME ;
    public $password    = PASSWORD ;
    public $dbName      = DB_NAME ;

    public $pdo;
    public $error;

    public function __construct()
    {
        $this->db_connect();        
    }

    private function db_connect()
    {
        try {
            $pdo = new PDO("mysql:host=$this->serverName;dbname=$this->dbName", 
                   $this->userName, $this->password);    
            $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
            //echo 'Connected successfully'; 
            }

        catch(PDOException $e)
        {
        echo "Connection failed: " . $e->getMessage();
        }
    }
    public function userIndex($query)
    {       
        //$stmt = $this->pdo->query($query);
        $stmt = $this->pdo->prepare($query);
        $stmt->execute();

        if($stmt-> rowCount() > 0)
        {
            return $read;
        }
        else
        {
        return false;
        }
    }

}

**这是我的**

    <?php
    session_start();    
    include('../../class/config.php');
    include('../../class/DatabaseFunctions.php');
    if(isset($_SESSION['user'])) {

    $db=new DatabaseFunctions();
    $query='SELECT * FROM members';
    $read=$db->userIndex($query);   
    print_r($read); 
    ?>

致命错误：未捕获错误：在null上调用成员函数query（）在 D：\ Laravel \ Xamp_new \ htdocs \ mou \ bikroy \ bikroyplus \ class \ DatabaseFunctions.php：33 堆栈跟踪：＃0 D：\ Laravel \ Xamp_new \ htdocs \ mou \ bikroy \ bikroyplus \ admin \ pages \ users.php（12）： DatabaseFunctions-> userIndex（'SELECT * FROM m ...'）＃1 {main}被抛出 D：\ Laravel \ Xamp_new \ htdocs \ mou \ bikroy \ bikroyplus \ class \ DatabaseFunctions.php 在第33行

是错误..请帮助我.. 注意：数据库已成功连接。但没有pdo函数有效。它说调用成员函数。请帮我。

Answer 1

在connect函数中，$pdo仅在函数内部定义，您需要将其分配给$this->pdo ...

function db_connect() { 
    try { 
        $this->pdo = new PDO("mysql:host=$this->serverName;dbname=$this->dbName", 
            $this->userName, $this->password); 
        $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 

        //echo 'Connected successfully'; 
    } catch(PDOException $e) { 
        echo "Connection failed: " . $e->getMessage(); 
    } 
}

致命错误：未捕获的错误：在null上调用成员函数query（）/ prepare（）。 PDO功能不起作用。总是说调用成员函数

1 个答案: