Question

我在这里遵循了这个教程：http://culttt.com/2012/10/01/roll-your-own-pdo-php-class/并编写了以下课程。

database.class.php

<?php

require_once './dbconfig.inc.php';

/**
 * MySQL Database PDO Wrapper Class.
 */
class Database {

    private $db_host = DB_HOST;
    private $db_user = DB_USER;
    private $db_name = DB_NAME;
    private $db_pass = DB_PASS;
    private $dbh;
    private $error;
    private $stmt;

    public function __construct() {
        $dsn = 'mysql:host=' . $this->db_host . ';dbname=' . $this->db_name;
        $options = array(
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8'//careful with this one, though
        );

        try {
            $dbh = new PDO($dsn, $this->db_user, $this->db_pass, $options);
        } catch (PDOException $ex) {
            $this->error = $ex->getMessage();
            echo $this->error;
        }
    }

    public function query($sql) {
        $this->stmt = $this->dbh->prepare($sql);
    }

    public function bind($param, $value, $type = null) {
        if (is_null($type)) {
            switch (true) {
                case is_int($value):
                    $type = PDO::PARAM_INT;
                    break;
                case is_bool($value):
                    $type = PDO::PARAM_BOOL;
                    break;
                case is_null($value):
                    $type = PDO::PARAM_NULL;
                    break;
                default:
                    $type = PDO::PARAM_STR;
            }
        }
        $this->stmt->bindValue($param, $value, $type);
    }

    public function execute() {
        return $this->stmt->execute();
    }

    public function getRows() {
        $this->execute();
        $this->stmt->fetchAll();
    }

    public function getRow() {
        $this->execute();
        $this->stmt->fetch();
    }

    public function rowCount() {
        return $this->stmt->rowCount();
    }

}

dbconfig.inc.php

<?php

define('DB_HOST', 'localhost');
define('DB_USER', 'root');
define('DB_NAME', 'hms');
define('DB_PASS', 'root');

demo.php

<?php

require_once './database.class.php';

$db = new Database();

$db->query('SELECT * FROM appointment');

$result = $db->getRows();
print_r($result);

连接成功但demo.php没有显示任何内容。在Chrome上，它返回500内部服务器错误。我在CentOS上运行LAMP堆栈中的脚本。我的数据库服务器是MariaDB 5.5

非常感谢任何有关其不起作用的反馈。

Answer 1

@Philipp是对的。你应该return来自函数。

所以如果提供你肯定需要：

public function getRows() {
    $this->execute();
    return $this->stmt->fetchAll();
}

检查@ Fred-ii-评论： require_once＆＃39; ./ database.class.php＆＃39 ;;但你声称你的文件是 dbclass.inc.php - 我称之为＆＃34;文件未找到＆＃34;。

更新在此处更改：

 public function getError() {
    return $this->error ;
 }
 public function __construct() {
    $dsn = 'mysql:host=' . $this->db_host . ';dbname=' . $this->db_name;
    $options = array(
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8'//careful with this one, though
    );

    try {
        $this->dbh = new PDO($dsn, $this->db_user, $this->db_pass, $options);
        $this->error = 'ok';
    } catch (PDOException $ex) {
        $this->error = $ex->getMessage();
    }
}

并在demo.php中更改为：

$db = new Database()
if (($err = $db->getError())=='ok') {
  ...
} else {
  echo $err;
}

PDO类甚至不工作

1 个答案: