Help with a php script .. User registration / email activation...

Okay guys, I need a little help - I have a php based website that I am building and I have the user membership / registration working. Meaning when someone registers it inserts the email, name, and password (md5) into the database, along with the randomly generated activation code that I have the registration script cook up. Now, They receive the e-mail and click the link for activation. I need to be able to when they click the link to activate the account have them type in their e-mail and/or activation code from the e-mail and then have the database update the table 'confirm_activation' to 1 instead of 0 this should allow the user's to actually get to the dashboard and use the site. I have everything working up until the point of the confirm_activation being able to switch from 0 to 1 upon successful activation. I am using mysqli as my DB connection. Here is the code:

register-auth.php

<?php
   
    require 'connection.php';
   
   
    $chars = array("1","2","3","4","5","6","7","8","9");
    $length = 6;
    $textstr = " ";
    for ($i=0; $i<$length; $i++) {
        $textstr .= $chars[rand(0, count($chars)-1)];
    }
   
   
    if(count($_POST) !== 3)
    {
        echo 'Please fill all the fields.';
    }


    if (!($stmt = $link->prepare("INSERT INTO users (name, email, password, activation) VALUES (?, ?, ?, ?)"))) {
        echo "Prepare failed: (" . $link->errno . ") " . $link->error;
    }
   
    $stmt->bind_param("sssi", $_POST['fullName'], $_POST['email'], md5($_POST['password']), $textstr);
   
    if (!$stmt->execute()) {
        echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
    }
   
       


    echo "Activation Email Sent.";

    $mail_to= $_POST['email'];
    $mail_subject="Email Activation - ISE";
    $mail_body.="This email will activate your account with ISE.<br>\r\n";
    $mail_body.="Your Activation Code is: $textstr <br> \r\n";
    $mail_body.="Click the following link to activate now.<br> \r\n";
    $mail_body.="<a href='http://steelcitydevstudios.com/dev/ise/activation-form.php?username=$username&activation=$textstr'>Click Here</a>";
    $sent = mail($mail_to,$mail_subject,$mail_body,
    'MIME-Version: 1.0' . "\r\n" .
    'Content-type: text/html; charset=UTF-8' . "\r\n" .
    'From: ise@steelcitydevstudios.com' . "\r\n" .
    'Reply-To: ise@steelcitydevstudios.com' . "\r\n" .
    'X-Mailer: PHP/' . phpversion());
       
    //} else {
    //    echo "Failed to send activation code, please contact support.";
    //}

?>

PHP:

acivation-form.php

<?php
    include_once('functions.php');
    displayHeader('Activation');
?>

<div class="row register">
        <div class="col-md-7">
            <div class="reg-box">
                <form class="register" name="reg-form" method="post" action="check-activation-script.php">
                    <div id="reg-logo">
                        <p class="reg">Finish Activation</p>
                            <img class="login-logo" src="/dev/ise/images/logo.png" alt="Information Security Education" width="296px" height="62px">
                    </div>
                        <hr>
                        <label class="login">Email:</label>
                            <input type="text" name="email" id="email" placeholder="" required autocomplete="off" >
                        <label class="login">Activation Code:</label>
                            <input type="text" name="activation_code" id="activation_code" placeholder="" required autocomplete="off" >
                            <input type="submit" id="continue" value="Activate">
                </form>
                       
                        <hr class="registerbox-btm">
                            <p>Already have an account? <a href="login.php">Login</a></p>
            </div>
        </div>
            <div class="col-md-5">
            <h1 class="register">Welcome To ISE!</h1>
                <h2 class="register-content">Here you’ll find the most advanced, efficient and fun employee training portal online!</h2> <br>
            <h1 class="register"> Scheduling, Training, Communication</h1>
                <h2 class="register-content">Use our dashboard and communication portal to establish training sessions for your employee’s or set your training times and collaborate ith your employer.</h2> <br>
            <h1 class="register">Train, Quiz, Get Certified!</h1>
                <h2 class="register-content">View our premium training videos, while answering our test questions as a popup inside the video! Get a passing mark and receive a ISE certification!</h2>
        </div>

</div>



                       
                       



<?php
    displayFooter();
?>

PHP:

check-activation.php

<?php
   
    require 'connection.php';
   
   
    $email = $_POST['email'];
    $activation_code = $_POST['activation_code'];
    //$command = "UPDATE users SET check_activation='1' WHERE email='$email' AND activation='$activation_code'";
       
        if (!($stmt = $link->prepare("UPDATE users SET check_verification VALUE (?) WHERE email='$email' AND activation='$activation'")));
   
    $stmt->bind_param('i', $activation_status);
   
    $activation_status = 1;   
   
    $stmt->execute();

    $result = mysql_query($command);
    if ($result) {
        echo "Congratulations, Your account has been successfully activated! You may now begin using our site.";
    } else {
        echo "Youve entered an invalid activation code / email. - Please try again.";
    }
   
    ?>

PHP:

database table (users)

CREATE TABLE IF NOT EXISTS `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `email` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  `name` varchar(255) COLLATE utf8_unicode_ci NOT NULL COMMENT 'user''s name',
  `password` varchar(255) COLLATE utf8_unicode_ci NOT NULL COMMENT 'will be case-sensitive',
  `active` enum('N','Y') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'N' COMMENT 'is this user active?',
  `deleted` enum('N','Y') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'N' COMMENT 'is the user deleted?',
  `is_god` enum('N','Y') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'N',
  `accountType` int(11) NOT NULL COMMENT '0=Employee, 1=Company, 2=Site_Admin',
  `activation` int(6) NOT NULL DEFAULT '0',
  `check_activation` int(6) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci COMMENT='The backend users' AUTO_INCREMENT=16 ;

Code (SQL):

the url is http://steelcitydevstudios.com/dev/ise/register.php

 

Why are you using enum('N','Y') on the active and deleted columns? Why not just use tinyint (boolean) 1/0?
Second, if you have sent a user a link, then all you need to do is use that link - there's no reason for the user to fill out even more forms?
Send the user a link containing the user's email, and the unique activation code, something like this: http://www.example.com?page=activate&email=something@example.com&activationcode=asbd4w798347sase
Then you check if that activation code matches the one in the DB for the user with that email-address, and if it does, you flip the value to 1.