Online Voting System with PHP & MySQL

Online voting system is one of the best way to get user opinion about any topic. Now a days, most of the news and sports sites usually have this system.

So in this tutorial I am going create an online voting system using PHP and MySQL with IP restriction. I will use the example of top football player.

Voting System with PHP & MySQL:

This system will have 3 files which are:

Config.php:File having MySQL database connection
Functions.php: This file will have custom PHP functions which will fetch result/count from MySQL database.
Index.php: This file will have HTML and PHP section. At the top of the file there will be PHP Code. After PHP code there will be HTML code for polling question and its result. Also I will be using bootstrap 4 for styling.

Create Database:


Create database demo;

Create database demo;

Create Table:


CREATE TABLE `footballer_poll` (
	`id` INT(11) NOT NULL AUTO_INCREMENT,
	`footballer_name` VARCHAR(100) NULL DEFAULT NULL,
	`user_ip` VARCHAR(50) NULL DEFAULT NULL,
	PRIMARY KEY (`id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
AUTO_INCREMENT=1;

CREATE TABLE `footballer_poll` (

`id` INT(11) NOT NULL AUTO_INCREMENT,

`footballer_name` VARCHAR(100) NULL DEFAULT NULL,

`user_ip` VARCHAR(50) NULL DEFAULT NULL,

PRIMARY KEY (`id`)

)

COLLATE='latin1_swedish_ci'

ENGINE=InnoDB

AUTO_INCREMENT=1;

Config.php:


<?php    
    $dsn = 'mysql:dbname=demo;host=localhost';
    $user = 'root';
    $password = '';

    try
    {
        $pdo = new PDO($dsn,$user,$password);
        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }
    catch(PDOException $e)
    {
        echo "PDO error".$e->getMessage();
        die();
    }
?>

<?php

$dsn = 'mysql:dbname=demo;host=localhost';

$user = 'root';

$password = '';

try

{

$pdo = new PDO($dsn,$user,$password);

$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

}

catch(PDOException $e)

{

echo "PDO error".$e->getMessage();

die();

}

Above code has PHP PDO connection in try and catch block. I also set an attribute for error exception.

Functions.php:


<?php
function getAllResults()
{
	global $pdo;
	$sql = 'select count(id) as total from footballer_poll';
	$handle = $pdo->prepare($sql);
	$handle->execute();
	$count = $handle->fetch(PDO::FETCH_ASSOC);
	return $count['total'];
}

function getResultByName($name)
{
	global $pdo;
	$sql = 'select count(id) as total from footballer_poll where footballer_name = :name ';
	$handle = $pdo->prepare($sql);
	$param = ['name' => $name];
	$handle->execute($param);
	$count = $handle->fetch(PDO::FETCH_ASSOC);
	return $count['total'];
}

function getSinglePlayerData($playerName){
	global $pdo;

	$getAllCount = getAllResults();
	$getPlayerCount = getResultByName($playerName);
	$calculate = $getPlayerCount/$getAllCount * 100;
	return number_format($calculate,2,)."%";
}

function ifIPIsExist($ip){
	global $pdo;
	$sql = 'select * from footballer_poll where user_ip = :ip ';
	$handle = $pdo->prepare($sql);
	$param = ['ip' => $ip];
	$handle->execute($param);
   
	return ($handle->rowCount() > 0) ?? TRUE;
}
?>

<?php

function getAllResults()

{

global $pdo;

$sql = 'select count(id) as total from footballer_poll';

$handle = $pdo->prepare($sql);

$handle->execute();

$count = $handle->fetch(PDO::FETCH_ASSOC);

return $count['total'];

}

function getResultByName($name)

{

global $pdo;

$sql = 'select count(id) as total from footballer_poll where footballer_name = :name ';

$handle = $pdo->prepare($sql);

$param = ['name' => $name];

$handle->execute($param);

$count = $handle->fetch(PDO::FETCH_ASSOC);

return $count['total'];

}

function getSinglePlayerData($playerName){

global $pdo;

$getAllCount = getAllResults();

$getPlayerCount = getResultByName($playerName);

$calculate = $getPlayerCount/$getAllCount * 100;

return number_format($calculate,2,)."%";

}

function ifIPIsExist($ip){

global $pdo;

$sql = 'select * from footballer_poll where user_ip = :ip ';

$handle = $pdo->prepare($sql);

$param = ['ip' => $ip];

$handle->execute($param);

return ($handle->rowCount() > 0) ?? TRUE;

}

As you can see in above code I have written 4 functions. Each function have global $pdo that will get the value (in our case db object) of $pdo from global namespace. getAllResults() returns total count of vote. getResultByName() functions returns count of specific footballer. getSinglePlayerData() returns the percentage of vote against specific player and ifIPIsExist checks the IP address of current user. If current already vote with current IP then it will return 1 otherwise empty.

Index.php


<?php 
    require_once('config.php');
    require_once('functions.php');

    if(isset($_POST['submit']))
    {
        if(isset($_POST['footballer']) && !empty($_POST['footballer']))
        {
            $footballerName = $_POST['footballer'];
            $clientIP = $_SERVER['REMOTE_ADDR'];
            $checkIfIpExist = ifIPIsExist($clientIP);

            if($checkIfIpExist == 1)
            {
                $errorMsg = 'You already cast your vote.';
            }
            else
            {
                $sql = 'insert into footballer_poll (footballer_name,user_ip) values(:name,:ip)';
                $handle = $pdo->prepare($sql);
                
                $params = [
                    'name' => $footballerName,
                    'ip' =>$clientIP
                ];

                $handle->execute($params);
                
                if($handle->rowCount())
                {
                    $successMsg = 'Thank you! For your vote';
                }
                else
                {
                    $errorMsg = 'Unable to save your vote. Try again later';
                }

                
            }
        }
        else
        {
            $errorMsg = 'Please pick one footballer';
        }
        
    }

    $ronaldoCount = getSinglePlayerData('Cristiano Ronaldo');
    $messiCount = getSinglePlayerData('Lionel Messi ');
    $neymarCount = getSinglePlayerData('Neymar');
    $salahCount = getSinglePlayerData('Muhammad Salah');
?>
<!doctype html>
<html lang="en">
  <head>
    
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/css/bootstrap.min.css" integrity="sha384-TX8t27EcRE3e/ihU7zmQxVncDAy5uIKz4rEkgIXeMed4M0jlfIDPvg6uqKI2xXr2" crossorigin="anonymous">
    <title>Demo - Online Voting System with php and MySQL</title>
  </head>
  <body >
  <div class="container mt-1 p-3 text-center">
    <h1>Online Voting System with PHP MySQL</h1>
  </div>
    <div class="container mt-1 p-3 border">
    
    <h2>Vote for Best Footballer:</h2>
        <?php 
            if(isset($errorMsg))
            {
                echo '<div class="alert alert-danger">'.$errorMsg.'</div>';
            }

            if(isset($successMsg))
            {
                echo '<div class="alert alert-success">'.$successMsg.'</div>';
            }
        ?>
        <form class="" method="post" action="<?php $_SERVER['PHP_SELF']?>">
            <div class="row ">
                <div class="col-md-6 ">
                    <div class="custom-control custom-radio">
                        <input type="radio" class="custom-control-input" id="footballer1" name="footballer" value="Cristiano Ronaldo">
                        <label class="custom-control-label" for="footballer1">Cristiano Ronaldo</label>
                    </div>
                </div>
            </div>
            <div class="row">
                <div class="col-md-6">
                    <div class="custom-control custom-radio">
                        <input type="radio" class="custom-control-input" id="footballer2" name="footballer" value="Lionel Messi">
                        <label class="custom-control-label" for="footballer2">Lionel Messi</label>
                    </div>
                </div>
            </div>
            <div class="row">
                <div class="col-md-6">
                    <div class="custom-control custom-radio">
                            <input type="radio" class="custom-control-input" id="footballer3" name="footballer" value="Neymar">
                            <label class="custom-control-label" for="footballer3">Neymar</label>
                    </div>
                </div>
            </div>
            <div class="row">
                <div class="col-md-6">
                    <div class="custom-control custom-radio">
                            <input type="radio" class="custom-control-input" id="footballer4" name="footballer" value="Muhammad Salah">
                            <label class="custom-control-label" for="footballer4">Muhammad Salah
</label>
                        </div>
                </div>
            </div>
            <div class="row">
                <div class="col-md-6 pt-2">
                    <button type="submit" name="submit" class="btn btn-danger">Vote</button>
                </div>
            </div>   
        </form>

    </div>
    <div class="container mt-3 border p-3">
    <h2>Result: Vote for Best Footballer</h2>
        <div class="row">
            <div class="col-md-2">Cristiano Ronaldo</div>
            <div class="col-md-6">
                <div class="progress mb-2">
                    <div class="progress-bar progress-bar-striped progress-bar-animated" style="width:<?php echo $ronaldoCount?>"><?php echo $ronaldoCount?></div>
                </div>
            </div>
         </div>   
         <div class="row">
            <div class="col-md-2">Lionel Messi </div>
            <div class="col-md-6">
            <div class="progress mb-2">
                <div class="progress-bar bg-success progress-bar-striped progress-bar-animated" style="width:<?php echo $messiCount?>"><?php echo $messiCount?></div>
            </div>
            </div>
         </div>   
         <div class="row">
            <div class="col-md-2">Neymar</div>
            <div class="col-md-6">
                <div class="progress mb-2">
                    <div class="progress-bar bg-warning progress-bar-striped progress-bar-animated" style="width:<?php echo $neymarCount?>"><?php echo $neymarCount?></div>
                </div>
            </div>
         </div>   
         <div class="row">
         <div class="col-md-2">Muhammad Salah</div>
            <div class="col-md-6">
                <div class="progress mb-2">
                    <div class="progress-bar bg-danger progress-bar-striped progress-bar-animated" style="width:<?php echo $salahCount?>"><?php echo $salahCount?></div>
                </div>
            </div>
         </div>   
    </div>
    
    <script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/bootstrap@4.5.3/dist/js/bootstrap.bundle.min.js" integrity="sha384-ho+j7jyWK8fNQe+A12Hb8AhRq26LrZ/JpcUGGOn+Y7RsweNrtN/tE3MoK7ZeZDyx" crossorigin="anonymous"></script>

   
  </body>
</html>

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<?php

require_once('config.php');

require_once('functions.php');

if(isset($_POST['submit']))

{

if(isset($_POST['footballer']) && !empty($_POST['footballer']))

{

$footballerName = $_POST['footballer'];

$clientIP = $_SERVER['REMOTE_ADDR'];

$checkIfIpExist = ifIPIsExist($clientIP);

if($checkIfIpExist == 1)

{

$errorMsg = 'You already cast your vote.';

}

else

{

$sql = 'insert into footballer_poll (footballer_name,user_ip) values(:name,:ip)';

$handle = $pdo->prepare($sql);

$params = [

'name' => $footballerName,

'ip' =>$clientIP

];

$handle->execute($params);

if($handle->rowCount())

{

$successMsg = 'Thank you! For your vote';

}

else

{

$errorMsg = 'Unable to save your vote. Try again later';

}

else

{

$errorMsg = 'Please pick one footballer';

}

$ronaldoCount = getSinglePlayerData('Cristiano Ronaldo');

$messiCount = getSinglePlayerData('Lionel Messi ');

$neymarCount = getSinglePlayerData('Neymar');

$salahCount = getSinglePlayerData('Muhammad Salah');

<!doctype html>

<head>

<title>Demo - Online Voting System with php and MySQL</title>

</head>

<body >

<h1>Online Voting System with PHP MySQL</h1>

</div>

<h2>Vote for Best Footballer:</h2>

<?php

if(isset($errorMsg))

{

echo '<div class="alert alert-danger">'.$errorMsg.'</div>';

}

if(isset($successMsg))

{

echo '<div class="alert alert-success">'.$successMsg.'</div>';

}

<label class="custom-control-label" for="footballer1">Cristiano Ronaldo</label>

</div>

<label class="custom-control-label" for="footballer2">Lionel Messi</label>

</div>

<label class="custom-control-label" for="footballer3">Neymar</label>

</div>

<label class="custom-control-label" for="footballer4">Muhammad Salah

</label>

</div>

</div>

</form>

</div>

<h2>Result: Vote for Best Footballer</h2>

<div class="col-md-2">Cristiano Ronaldo</div>

</div>

<div class="col-md-2">Lionel Messi </div>

</div>

<div class="col-md-2">Neymar</div>

</div>

<div class="col-md-2">Muhammad Salah</div>

</div>

</body>

</html>

First of all index file include config.php and functions.php. After that there is vote form submit logic with error and success message. I have used $_SERVER['REMOTE_ADDR'] to get current user IP address and match with database IPs.

Note: $_SERVER[‘REMOTE_ADDR’] sometimes may not return correct IP address.