MySQL code only gets executed once rather than multiple times in a loop

Question

<?PHP
session_start();
if (isset($_SESSION['hasVoted']) && $_SESSION['hasVoted'] == '1') {
        print "You've already voted";
    }
else {
    if (isset($_POST['Submit1'])) {
        $ID = $_SESSION['user']; // obtain the ID of the user from the login session
        var_dump($ID);
        $string_results = $_POST['h2'];
        $selected_radio = explode(',', $string_results);
        var_dump($selected_radio);
        $user_name = "root";
        $password = "";
        $database = "surveyTest";
        $server = "127.0.0.1";
        $SQL = "SELECT * FROM tblquestions";
        $db_handle = mysql_connect($server, $user_name, $password);
        $db_found = mysql_select_db($database, $db_handle);
        if ($db_found) {
            $result = mysql_query($SQL);
            $numRows = mysql_num_rows($result); //return number of rows in the table
            var_dump($numRows);
            $qNum = 'q1';
            for ($i = 0; $i < $numRows; $i++)
            {
                var_dump($qNum);
                $_SESSION['hasVoted'] = '1';
                $selected_Value = $selected_radio[$i];
                var_dump($selected_Value);
            //==================================================================================
            //  SET Multiple rows IN THE answers TABLE for each question for a given student.
            //==================================================================================
                $SQL = "INSERT INTO answers (QID, Answer, SID) VALUES ('$qNum', '$selected_Value', '$ID')";
                $result = mysql_query($SQL);
                    $question_Number = ltrim($qNum,'q');
                    $question_Number++;
                    $qNum ='q'.$question_Number;
            }
                mysql_close($db_handle);
                print "Thank you for participating!";
        }
        else {
        print "database error";
        }
    }

    else {
        header("location:login.php");;
    }
}
session_destroy();
?>

<html>
<head>
<title>Process Survey</title>
</head>



<body>

</body>
</html>

When I execute the above code, the $SQL statement that consists of the INSERT only gets executed once. This means that it is only adding a single record to the database. However, I need it to add several records to the database which is equal to $numRows. The print out of $qNum and $selected_Value show the right thing. Any suggestions?

Add a call to mysql_error, and see if the database is generating an error. You're also doing a lot of work to generate $qNum - doesn't it just have the value of "q" . ($i + 1)? — andrewsi
– andrewsi, Commented Jul 9, 2013 at 20:19
Never trust user input! If you don't check user-supplied variables, you will get hacked after a few days (if you're lucky)... — mimipc
– mimipc, Commented Jul 9, 2013 at 20:22

kbariotis · Accepted Answer · 2013-07-09 20:23:00Z

2

try again using $result = mysql_query($SQL) or die(mysql_error());

also are the Primary keys ok on your table?

answered Jul 9, 2013 at 20:23

kbariotis

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3 Comments

Ahmed Ebaid Over a year ago

Thanks for this, this is one thing that I missed. So, to find out the error is it just echo mysql_errno($db_handle)

Jacob S Over a year ago

mysql_error, not mysql_errno which will not give you as useful information.

kbariotis Over a year ago

no just the above code and PHP will print out any faults you might have.

StackSlave · Accepted Answer · 2013-07-09 20:51:06Z

0

In order for your code to work correctly you would have to have the same number in your $numRows variable, which is based on your $result variable, as you do in count($selected_radio), which is probably not the case. I'm also concerned that you may not have an HTML <input type='radio' value='whatever' name='h2' />. Why would this be a comma separated String? A radio button should only return the value which is 'checked'. Anyways, maybe you have name='h2', in a hidden input or something. In this case your loop should look something like:

for($i=0,$l=count($selected_radio); $i<$l; $i++){
  //your code in here
}

If I was you I would use a Library like PHPglue to handle your Sticky Form issues. Visit https://www.PHPglue.com for more details.

answered Jul 9, 2013 at 20:51

StackSlave

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1 Comment

Ahmed Ebaid Over a year ago

In my case, h2 is a hidden input type.

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