Question

我在标题为sample.php的PHP文件中跟踪了一个函数的代码：

function deleteValue($value) {

  $servername = "localhost";
  $username = "root";
  $password = "jumbo";
  $dbname = "demo";

  // Create connection
  $conn = new mysqli($servername, $username, $password, $dbname);
  // Check connection
  if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
  }

  $sql = "DELETE FROM user WHERE value = '$value'";

  if ($conn->query($sql) === TRUE) {
    $conn->close();     
    return true;
  } else {
    $conn->close();     
    return false;
  }  
}

实际上，在这个文件（sample.php）中有太多这样的函数会重复以下数据库连接代码：

      $servername = "localhost";
      $username = "root";
      $password = "jumbo";
      $dbname = "demo";

      // Create connection
      $conn = new mysqli($servername, $username, $password, $dbname);
      // Check connection
      if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
      }

然后，我在同一文件夹中创建了一个标题为db.php的文件，并将上述代码添加到其中。在文件开头使用require_once('db.php'); sample.php＆＃39;我将文件包含在上面的代码中。最后代码如下：

require_once('db.php');
function deleteValue($value) {

      $sql = "DELETE FROM user WHERE value = '$value'";

      if ($conn->query($sql) === TRUE) {
        $conn->close();     
        return true;
      } else {
        $conn->close();     
        return false;
      }  
    }

现在它给了我500内部服务器错误。

甚至不是通过在文件db.php的开头粘贴sample.php的整个代码来尝试包含我尝试过的文件，但仍然会出现500内部服务器错误。

$servername = "localhost";
  $username = "root";
  $password = "jumbo";
  $dbname = "demo";

  // Create connection
  $conn = new mysqli($servername, $username, $password, $dbname);
  // Check connection
  if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
  }

function deleteValue($value) {

  $sql = "DELETE FROM user WHERE value = '$value'";

  if ($conn->query($sql) === TRUE) {
    $conn->close();     
    return true;
  } else {
    $conn->close();     
    return false;
  }  
}

有人可以纠正我在我的代码中犯的错误吗？

提前致谢。

Answer 1

我建议你在 db_config.php 文件中，你应该只使用数据库配置和这样的函数：

$servername = "localhost";
$username = "root";
$password = "jumbo";
$dbname = "jumbo_jet";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_errno) {
    echo "Failed to connect to MySQL: (" . $conn->connect_errno . ") " . $conn->connect_error;
}

在 common.php 中使用这样的代码：

require_once("db_config.php");

function deleteToken($receivedToken) {
  global $conn;
  $sql = "DELETE FROM user_login WHERE token = '$receivedToken'";

  if ($conn->query($sql) === TRUE) {
    return true;
  }
  return false;
}

我希望它对你有用。如果有的话，请告诉我。

为什么require_once在以下场景中不起作用？

1 个答案: