php - 如何防止重新执行查询php + mysql

Question

我正在学习 PHP 和 MySQL。我决定玩一点，我制作了一个动态页面，我用 MySQL 和 if 循环实现了它(我不在乎它是否值得，只是为了好玩)。

代码看起来像这个例子:

mysqli_query($conn,"UPDATE something SET something = something + 1 WHERE id = " . $_GET['id']

   if(mysqli_num_rows($result) > 0){
    while($row = mysqli_fetch_assoc($result)){
  echo table;
    }
    }

每次有人单击子页面上的链接时，它都会将 $_GET['id'] 传递给上面的代码。一切正常，但是......但是在刷新页面后，使用更新语句的查询正在“重新执行”(我不知道它是否正确 - 英语不是我的母语)和标题('Location:')不起作用...它只显示“找不到页面”。

有什么办法可以防止刷新后重新执行查询吗？

Answer 1

<?php
    session_start(); //you call this to use session variables

   if(isset($_SESSION['details']) && $_SESSION['details']==true)
   { /*do nothing since query has ran once*/}
   else
   {
    /*run query since query has not been run*/
    mysqli_query($conn,"UPDATE something SET something = something + 1 WHERE id = " .$_GET['id'];
     $_SESSION['details']=true; //you set a session variable to true when query runs the first time.
    }

    /*i am assuming there is a select statement here that retruns the **$result** */
    if(mysqli_num_rows($result) > 0)
    {
     while($row = mysqli_fetch_assoc($result))
     {
      echo table;
     }
    }
 ?>