Question

当我尝试通过OOP方法构建连接时，我遇到了一些错误。我使用了两个文件databse.php和config.php。

这是我的'database.php'

<?php
require_once 'functions.php';
require_once 'config.php';
/**
 *
 */
class Database{

  private $connection;
  public $name;

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

  public function open_connection() {
    $this->connection = mysqli_connect(DB_SERVER, DB_USER, DB_PASS, DB_NAME);
    if (!$this->connection) {
      echo mysqli_error($this->connection);
    }
    }

  public function query($sql){
    $result_set = mysqli_connect($this->connection, $sql);
    while ($result = mysqli_fetch_array($result_set)) {
    $this->name = $result['name'];
    }
  }

}

$db = new Database();
$db->query("SELECT * FROM items");
?>

这里是'config.php'

<?php
defined('DB_SERVER') ? null : define('DB_SERVER', 'localhost');
defined('DB_USERNAME') ? null : define('DB_USERNAME', 'root');
defined('DB_PASSWORD') ? null : define('DB_PASSWORD', 'root');
defined('DB_NAME') ? null : define('DB_NAME', 'cafe');
?>

错误是：

Notice: Use of undefined constant DB_USER - assumed 'DB_USER' in /var/www/html/cafe/includes/database.php on line 17

Notice: Use of undefined constant DB_PASS - assumed 'DB_PASS' in /var/www/html/cafe/includes/database.php on line 17

Warning: mysqli_connect(): (HY000/1045): Access denied for user 'DB_USER'@'localhost' (using password: YES) in /var/www/html/cafe/includes/database.php on line 17

Warning: mysqli_error() expects parameter 1 to be mysqli, boolean given in /var/www/html/cafe/includes/database.php on line 19

Warning: mysqli_connect(): (HY000/1045): Access denied for user 'SELECT * FROM items'@'localhost' (using password: NO) in /var/www/html/cafe/includes/database.php on line 24

Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in /var/www/html/cafe/includes/database.php on line 25

Answer 1

按如下方式更改您的代码

  [
    {
      id: 1,
      title: 'Robinson Crusoe',
      author: 'Daniel Defoe',
      references: ['chp1_robincrusoe', 'chp2_robincrusoe'],
    },
    {
      id: 2,
      title: 'Gullivers Travels',
      author: 'Jonathan Swift',
      references: ['chp1_gulliverstravels', 'chp2_gulliverstravels', 'chp3_gulliverstravels'],
    },
  ]

Answer 2

您连接到某个未定义的值。

$this->connection = mysqli_connect(DB_SERVER, DB_USER, DB_PASS, DB_NAME);

DB_USER，DB_PASS未定义

其DB_USERNAME，DB_PASSWORD

defined('DB_USERNAME') ? null : define('DB_USERNAME', 'root');
defined('DB_PASSWORD') ? null : define('DB_PASSWORD', 'root');

我使用PHP7时数据库连接错误

2 个答案: