Inputting form data into Mysql database using php

Question

I'm very new to MySQL. I'm trying to create a php script which reads data from a html form and stores it into the database. I'm also uploading an image whose path is saved in database and the image itself is stored in c:wamp/www/uploads. Now when I'm running the script on my wamp server after submission of my form I'm getting a blank page. When i check my uploads folder, it's still empty. So image isn't put into the folder. Can anyone debug it?

<?php

define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_DATABASE', 'userdatadelta');

$db = mysqli_connect(DB_SERVER,DB_USERNAME,DB_PASSWORD,DB_DATABASE);

$table= "CREATE TABLE `users` 
        (  `rollno` int(15) NOT NULL,
           `name` varchar(50) NOT NULL,
           `email` varchar(50) NOT NULL,  
           `password` varchar(50) NOT NULL,  
           `imageid` varchar(50) NOT NULL,  
            PRIMARY KEY (`uid`),  
            UNIQUE KEY `username` (`email`))";

mysqli_query($db,$table);

if(isset($_POST["submit"]))
{
$name = $_POST["name"];
$roll_number = $_POST["rollno"];
$department = $_POST["department"];
$year = $_POST["year"];
$email = $_POST["email"];
$password = $_POST["password"];
$filename=$_FILES['userpic']['name'];
$filetype=$_FILES['userpic']['type']; 

$name = mysqli_real_escape_string($db, $name);
$roll_number = mysqli_real_escape_string($db, $roll_number);
$department = mysqli_real_escape_string($db, $department);
$year = mysqli_real_escape_string($db, $year);
$email = mysqli_real_escape_string($db, $email);
$password = mysqli_real_escape_string($db, $password);
$password = md5($password);

$newfilename= $roll_number;

if($filetype=='image/jpeg' or $filetype=='image/png' or $filetype=='image/gif')
 {
move_uploaded_file($_FILES['file']['tmp_name'],'upload/'.$newfilename);
$filepath="upload/".$newfilename;
 }


$sql = "SELECT email FROM users WHERE email='$email'";
$result = mysqli_query($db,$sql);
$row = mysqli_fetch_array($result,MYSQLI_ASSOC);

if(mysqli_num_rows($result) == 1)
{
 echo "An account has been created with this email ID already. We regret the inconvenience";
}
else
{
  $query = mysqli_query($db, "INSERT INTO users (name, rollno, department, year, email, password, imagepath)VALUES ( '$name','$roll_number', $department, $year,'$email', '$password', '$filepath')");

  if($query)
   {
    echo "Thank You! You have completed registration and are now registered.";
   }
}
}
?>

Edited code which works for the most part but for the insertion of data :(. The 2 comments "An account has been created with this email ID already. We regret the inconvenience" and "Thank You! You have completed registration and are now registered." don't seem to work.

<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);

$DB_SERVER="localhost";
$DB_USERNAME="root";
$DB_PASSWORD="";
$DB_DATABASE="userdatadelta";

$db = mysqli_connect( "$DB_SERVER" ,"$DB_USERNAME","$DB_PASSWORD","$DB_DATABASE")or die("Cannot connect");

echo "Got connected?";

if(isset($_POST["submit"]))
{
echo "Got inside isset!";
$name = $_POST["name"];
$roll_number = $_POST["rollno"];
$department = $_POST["department"];
$year = $_POST["year"];
$email = $_POST["email"];
$password = $_POST["password"];
$filename=$_FILES['userpic']['name'];
$filetype=$_FILES['userpic']['type']; 

$name = mysqli_real_escape_string($db, $name);
$roll_number = mysqli_real_escape_string($db, $roll_number);
$department = mysqli_real_escape_string($db, $department);
$year = mysqli_real_escape_string($db, $year);
$email = mysqli_real_escape_string($db, $email);
$password = mysqli_real_escape_string($db, $password);
$password = md5($password);

$newfilename= $roll_number;

if($filetype=='image/jpeg' or $filetype=='image/png' or $filetype=='image/gif')
 {
echo "Got inside file type checking!";
move_uploaded_file($_FILES['userpic']['tmp_name'],'upload/'.$newfilename);
$filepath="upload/".$newfilename;
 }


$sql = "SELECT email FROM users WHERE email='$email'";
$result = mysqli_query($db,$sql);
$row = mysqli_fetch_array($result,MYSQLI_ASSOC);

if(mysqli_num_rows($result) == 1)
{
 echo "An account has been created with this email ID already. We regret the inconvenience";
}
else
{
  $query = mysqli_query($db, "INSERT INTO users (name, rollno, department, year, email, password, imagepath)VALUES ( '$name','$roll_number', $department, $year,'$email', '$password', '$filepath')");
  echo "Got inside else!";
  if($query)
   {
    echo "Thank You! You have completed registration and are now registered.";
   }
}
}
echo "Comment!";
?> 

Answer 1

With such a long code snippet its hard to determine possible errors, as the blank page can be caused from many reasons.

Some of the typical problems that could be related to your code:

• a PHP syntax error like an extra or missing brace ( { or } ), for example. The piece you posted seems to be ok, but you dont't tell which PHP version are you using.

• a denied write permission to upload path. Either because permissions are wrong, or the path is incorrect. You don't specify your operating system, but it's assumed to be Windows. Some systems use case insensitive paths, other case sensitive, check that for the version and configuration of your current system.

• for blank page issue, even when no errors would be raised, there is a sequence of execution in which neither one of the two echo calls are being triggered.

Tipically, PHP will not output any errors to the users as in a production environment it may represent a security risk.

In your development environment you can enable error output to quickly address what is going wrong.

Add the following lines just right after the first opening <?php clause:

error_reporting(E_ALL);
ini_set("display_errors", 1);

Now all the errors for what PHP is complaining should be outputted to the browser.

Be aware, this is not considered a good practice specially in production environments. Errors should be looked up on log files. Use it for helping yourself debugging and solving your current problem in develpment time. If you are working on a large project consider getting the help of a PHP framework to enhance your coding experience.