Question

         <!----  Database File  --->
      <?php
      require_once 'config.php';

      class MySQLDatabase {

          private $connection;

          function __construct() {
              $this->open_connection();
          }

          public function open_connection() {
              $this->connection = mysqli_connect(DB_SERVER, DB_USER, DB_PASS, DB_NAME);
              if(!$this->connection) {
                  die("Database connection Failed: " .mysqli_error($this->connection));
              }else {
                  $db_select = mysqli_select_db($this->connection, DB_NAME);
                  if(!$db_select) {
                     die("Database connection Failed: " .mysqli_error($this->connection)); 
                  }
              }
          }

          public function close_connection() {
              if(isset($this->connection)) {
                  mysqli_close($this->connection);
                  unset($this->connection);
              }
          }

          public function query($sql) {
              $result = mysqli_query($sql, $this->connection);
              $this->confirm_query($result);
              return $result;

          }


          private function confirm_query($result) {
              if(!$result) {
                   die("Database connection Failed: " .mysqli_error($this->connection)); 
              }
          }


      }

      $database = new MySQLDatabase();
      $database->close_connection();

      ?>

      <!----Config FIle which ---->

      <?php
          defined('DB_SERVER') ? null : define("DB_SERVER","localhost");
          defined('DB_USER')   ? null : define("DB_USER", "faizy");
          defined('DB_PASS')   ? null : define("DB_PASS", "faizy");
          defined('DB_NAME')   ? null : define("DB_NAME", "photo_gallery");
      ?>

      <!---index.php---->

      <!DOCTYPE html>
      <html lang="en">

      <head>
          <meta charset="UTF-8">
          <title>Document</title>
      </head>

      <body>
          <?php
          require_once '../includes/database.php';
          if(isset($database)){ echo "true"; } else { echo "false"; }
          echo "<h1>Working</h1>";
          ?>
      </body>

      </html>

以下是我的浏览器显示的警告和通知，任何人都可以建议为什么会这样，当我使用单个php并尝试连接它连接时，但当我使用不同的函数文件并使用OOP php时总是这些错误是显示，任何人都可以帮助解决这些警告和通知

Notice: Use of undefined constant DB_SERVER - assumed 'DB_SERVER' in C:\xampp\htdocs\demo\oop\includes\database.php on line 13

Notice: Use of undefined constant DB_USER - assumed 'DB_USER' in C:\xampp\htdocs\demo\oop\includes\database.php on line 13

Notice: Use of undefined constant DB_PASS - assumed 'DB_PASS' in C:\xampp\htdocs\demo\oop\includes\database.php on line 13

Notice: Use of undefined constant DB_NAME - assumed 'DB_NAME' in C:\xampp\htdocs\demo\oop\includes\database.php on line 13

Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:\xampp\htdocs\demo\oop\includes\database.php on line 13

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:\xampp\htdocs\demo\oop\includes\database.php on line 13

Warning: mysqli_error() expects parameter 1 to be mysqli, boolean given in C:\xampp\htdocs\demo\oop\includes\database.php on line 15
Database connection Failed:

Answer 1

我刚刚使用三个单独文件中的所有上述代码进行了测试，这一切都适合我。我改变的只是数据库名称，并传递给我的数据库之一。您必须链接到错误的文件。

Answer 2

将常量定义置于数据库逻辑之上，它将起作用。这将确认您的需求路径配置不正确。

使用OOP php时注意和警告

2 个答案: