php - 我的 mysql 和 php 有问题

Question

我有一个问题，这是我的代码:

   $db = new mysqli("localhost", "root", "", "blah");

$result1 = $db->query("select * from c_register where email = '$eml' and password = '$pass'");

if($result1->fetch_array())

  {

        $auth->createSession();

        $_SESSION['user'] = 'client';

        promptUser("You have successfully logged in!!!","index.php");
  }

$db = new mysqli("localhost", "root", "", "blah");

$result2 = $db->query("select * from b_register where email = '$eml' and password = '$pass'");
  if($result2->fetch_array())

  {

         $auth->createSession();

         $_SESSION['user'] = 'business';

         promptUser("You have successfully logged in!!!","index.php");
  }
$db = new mysqli("localhost", "root", "", "blah");

$result3 = $db->query("select * from g_register where email = '$eml' and password = '$pass'");
  if($result3->fetch_array())

  {

        $auth->createSession();

        $_SESSION['user'] = 'employee';

        promptUser("You have successfully logged in!!!","index.php");
  }

$db = new mysqli("localhost", "root", "", "blah");

$result4 = $db->query("select * from k_register where email = '$eml' and password = '$pass'");
  if($result4->fetch_array())

  {

        $auth->createSession();

        $_SESSION['user'] = 'super';

        promptUser("You have successfully logged in!!!","index.php");
  }
  else

  {

        promptUser("Username/Password do not match.  Please try again!!!","");
  }

有趣的是，这段代码可以工作，但我不知道我的做法是错误的。我是 php 和 mysql 的新手，所以请帮忙。我还尝试了例如 result4->free(); 对于保存数据的所有变量，我收到此错误: fatal error :在非对象上调用成员函数 free() -对象在...

Answer 1

不要重复自己。您已经创建了 mysqli 对象，因此可以重用它。例如:

$db = new mysqli("localhost", "root", "", "blah");
$result1 = $db->query("select * from c_register...");
$result2 = $db->query("select * from d_register...");
$result3 = $db->query("select * from e_register...");

这将使您的代码更清晰，并且以后更容易修改。