PHP和SQL：使用登录会话变量无法正确更新数据库

Question

I am creating a page where a user can calculate their BMI and then save this to their profile. 我正在创建一个页面，用户可以在其中计算其BMI，然后将其保存到其个人资料中。 First I validate the BMI. 首先，我验证BMI。 However, when I perform this calculation now, it is inserting '0.99' into the database instead of the correct BMI value. 但是，当我现在执行此计算时，它将在数据库中插入“ 0.99”而不是正确的BMI值。 I have been debugging and think it has something to do with the connection to the database (have tried moving this around to other areas of the script but it isn't making a difference). 我一直在调试，并认为它与数据库的连接有关（尝试将其移至脚本的其他区域，但这没有什么影响）。

The code is below: 代码如下：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
    <title>Untitled Document</title>
</head>
<link rel="stylesheet" href="css.css" type="text/css" />
<body>
    <?php

    error_reporting(E_ALL &~ E_NOTICE);

    // Start the session
    session_start();


    // Make sure the browser is transmitting in UTF-8
    header('Content-type: text/html; charset=utf-8');

        // Clear the error message
    $error_msg = "";

    if (isset($_SESSION['user_id']))
        echo $_SESSION['user_id'];

    $dbc = mysqli_connect('localhost', 'root', 'root', 'help_me_be_healthy') or die("Error " . mysqli_error($dbc));
    mysqli_set_charset($dbc, "utf8");


    if(isset($_POST['submit']))
    {
        $bmi=0;
        $kg=$_POST['kg'];
        $mt=$_POST['mt'];

        if(empty($kg) || empty($mt))
        {
            echo "<label class='err'><center>All fields are required</center></label>";
            include("index.php");
        }

        else if(!is_numeric($kg) && !is_numeric($mt) )
        {
            echo "<label class='err'>Please enter valid data.</label>";
            include("index.php");
        }
        else
        {
            $bmi = $kg/($mt*$mt);
            $bmi=round($bmi,2);
            if ( $bmi <= 18.5 ) 
            {
                echo "Your BMI is " .$bmi."  which means you are underweight";

            }

            else if ( $bmi>18.5 && $bmi <= 24.9) {
                echo  "Your BMI is ".$bmi." which means you are normal";
            }

            else if ( $bmi>29.9 && $bmi> 24.9 ) {
                echo "Your BMI is ".$bmi." which means you are overweight";
            }

            else if ( $bmi >29.9 && $bmi<=39.9 ) {
                echo "Your BMI is ".$bmi." which means you are obese";

            }
            else
            {
                echo "You are morbidly obese.";

            } 
            include("index.php");

            //$query = "UPDATE `users` SET `user_bmi`= '$bmi' 
            //WHERE `user_id` = ($_SESSION = ['user_id'])";

            //echo $_SESSION['user_id'];



            //if (!isset($_GET['user_id'])) {
            //$query = "SELECT * FROM 'users'";
            $query = "UPDATE `users` SET `user_bmi`= '$bmi' WHERE `user_id` = '" . $_SESSION['user_id'] . "'";
            //}
            //else {
            //  $query = "UPDATE `users` SET `user_bmi`= '$bmi' WHERE `user_id` = '" . $_GET['user_id'] . "'";
            //}

            $data = mysqli_query($dbc, $query);
            $row = mysqli_fetch_assoc($data);
            print "\n----\nLookup:\n";
            print "Num rows: " . mysqli_num_rows($data);
            print "\n";
            print_r($row);
            print '</pre>';
            return;

        }
    }
    ?>
</body>
</html>

Any help would be much appreciated:) 任何帮助将非常感激：）

Sarah 莎拉

Answer 1

Assuming BMI is being calculated correctly/displayed, and the user_bmi column is a float/double/numeric/decimal, the UPDATE doesn't need quotes around the value so the SQL should be: 假设正确/显示了BMI，并且user_bmi float / double / numeric / decimal，则UPDATE不需要在该值user_bmi引号，因此SQL应该是：

$query = "UPDATE `users` SET `user_bmi`=$bmi WHERE `user_id`=".
    $_SESSION['user_id'];

( user_id my also not need to be escaped, depending if it's a number or a string) （ user_id我也不需要转义，取决于它是数字还是字符串）

Also, you cannot get a query result (fetch_assoc) from an UPDATE SQL command... if you'd like to know the number of effected rows use mysqli_affected_rows : 另外，您无法从UPDATE SQL命令获得查询结果（fetch_assoc）...如果您想知道受影响的行数，请使用mysqli_affected_rows ：

print "Num rows: ".mysqli_affected_rows($dbc);

What makes you think the BMI is going in incorrectly, are you sure the user_id is correct, how are you looking into the database to determine what's stored? 是什么让您认为BMI输入有误，您确定user_id是正确的，如何查看数据库以确定存储的内容？

Updated Code Printout code: 更新了代码打印输出代码：

if (!mysqli_query($dbc,$query)) {
   echo "Failed to store";
}
echo "<pre>\n----\nLookup:\nQuery:$query\n".
  "Num rows:".mysqli_affected_rows($dbc)."\n</pre>\n";

PHP和SQL：使用登录会话变量无法正确更新数据库

问题描述

1 个解决方案

解决方案1
0 已采纳 2013-10-31 22:22:41

PHP和SQL：使用登录会话变量无法正确更新数据库

问题描述

1 个解决方案

解决方案1 0 已采纳 2013-10-31 22:22:41

解决方案1
0 已采纳 2013-10-31 22:22:41