I’m trying to create a PHP registration script using PDO prepared statements with positional placeholders. But the MySQL queries don’t execute. var_dump(); doesn’t display any error.

I desperately need someone to closely look at my code and explain to me why the queries don’t execute.

Below is a rewrite of register.php, which now displays errors, if certain, predefined conditions are not met. However, it doesn’t display any error, when the insert or select query fail. var_dump(); doesn’t display any error either, even though PDO queries fail to execute.

Please, I need your help to fix this. Your time and input are much appreciated in advance. Thanks.

register.php:

<?php      // include configuration file     require ("includes/config.php");          //Class import for image uploading     //classes is the map where the class file is stored (one above the root)     include ("classes/upload/upload_class.php");                  // define variables and set to empty values        $firstnameErr = $lastnameErr = $usernameErr = $genderErr = $passwordErr = $confirmationErr = $emailErr = $birthdayErr = $phoneErr = "";       $firstname = $lastname = $username = $gender = $password = $confirmation = $email = $birthday = $phone = "";               // if form was submitted     if ($_SERVER["REQUEST_METHOD"] == "POST")     {                  $firstname = student_input($_POST["firstname"]);         $lastname = student_input($_POST["lastname"]);         $username = student_input($_POST["username"]);         $gender = student_input($_POST["gender"]);         $password = student_input($_POST["password"]);         $confirmation = student_input($_POST["confirmation"]);         $email = student_input($_POST["email"]);         $birthday = student_input($_POST["birthday"]);         $phone = student_input($_POST["phone"]);                          // validate submission         if (empty($_POST["firstname"]))         {             $firstnameErr = "First name is required.";         }         else         {                $firstname = student_input($_POST["firstname"]);         }         if(empty($_POST["lastname"]))         {             $lastnameErr = "Last name is required.";         }         else         {                $lastname = student_input($_POST["lastname"]);         }         if(empty($_POST["username"]))         {             $usernameErr = "Username is required.";         }         else if(!empty($_POST["username"]))         {              // validate username             if (!preg_match("/^[a-zA-Z0-9]*$/", $username))             {                 $usernameErr = "Username must contain only letters and numbers.";             }             if (strlen($username) < 4 || strlen($username) > 10)             {                 $usernameErr = "Username must be from 4 to 10 characters.";             }         }         else         {                $username = student_input($_POST["username"]);         }         if(empty($_POST["gender"]))         {             $genderErr = "Gender is required.";         }         else         {                $gender = student_input($_POST["gender"]);         }         if(empty($_POST["password"]))         {             $passwordErr = "Enter a password.";         }         else if(!empty($_POST["password"]))         {                        // validate username             if (!preg_match("/^[a-zA-Z0-9]*$/", $password))             {                 $passwordErr = "Password must contain letters, numbers and special characters.";             }             if (strlen($password) < 8 || strlen($password) > 20)             {                 $passwordErr = "Password must be from 8 to 20 characters.";             }         }         else if (empty($_POST["confirmation"]))         {             $confirmationErr = "Confirm your password.";         }         else if ($_POST["password"] != $_POST["confirmation"])         {             $confirmationErr = "Password and confirmation don't match.";         }         else         {             $password = student_input($_POST["password"]);         }         if(empty($_POST["email"]))         {             $emailErr = "Your email address is required.";         }         else if(!filter_var($email, FILTER_VALIDATE_EMAIL))         {             $emailErr = "Invalid email format";         }         else         {              $email = student_input($_POST["email"]);         }         if(empty($_POST["birthday"]))         {             $birthdayErr = "Birthday is required.";         }         else if(!empty($_POST["birthday"]))         {                $today = date("d-m-Y");                $diff = date_diff(date_create($birthday), date_create($today));                 if($diff->format('%y%') < 6)                {                    $birthdayErr = "You must be at least 6 years old to register.";                }                else                {                   $birthday = student_input($_POST["birthday"]);                                   }         }         if(empty($_POST["phone"]))         {             $phoneErr = "Phone number is required.";         }         else if(!empty($_POST["phone"]))         {                        // Don't allow country codes to be included (assumes a leading "+")              if (preg_match('/^(\+)[\s]*(.*)$/',$phone))             {                 $phoneErr = "You should not include the country code.";             }             // Remove hyphens - they are not part of a telephone number             $phone = str_replace ('-', '', $phone);                // Now check that all the characters are digits             if (!preg_match('/^[0-9]{10,11}$/',$phone))             {                 $phoneErr = "Phone number should be either 10 or 11 digits";             }                 // Now check that the first digit is 0             if (!preg_match('/^0[0-9]{9,10}$/',$phone))             {                 $phoneErr = "The telephone number should start with a 0";             }             else             {                           $phone = student_input($_POST["phone"]);             }         }         else if(!empty($_FILES["userimage"]))         {             //This is the directory where images will be saved              $max_size = 1024*250; // the max. size for uploading                  $my_upload = new file_upload;              $my_upload->upload_dir = "images/user/"; // "files" is the folder for the uploaded files (you have to create this folder)             $my_upload->extensions = array(".png", ".gif", ".jpeg", ".jpg"); // specify the allowed extensions here             // $my_upload->extensions = "de"; // use this to switch the messages into an other language (translate first!!!)             $my_upload->max_length_filename = 50; // change this value to fit your field length in your database (standard 100)             $my_upload->rename_file = false;                      $my_upload->the_temp_file = $_FILES['userimage']['tmp_name'];             $my_upload->the_file = $_FILES['userimage']['name'];             $my_upload->http_error = $_FILES['userimage']['error'];             $my_upload->replace = "y";             $my_upload->do_filename_check = "n"; // use this boolean to check for a valid filename          if ($my_upload->upload()) // new name is an additional filename information, use this to rename the uploaded file             {                 $full_path = $my_upload->upload_dir.$my_upload->file_copy;                 $imagename = $my_upload->file_copy;              }              else              {                  $imagename = "";              }         }         else         {              try             {                $stmt = $pdo->prepare("SELECT * FROM users WHERE username = ?");             $stmt->execute(student_input($_POST["username"]));             $user = $stmt->fetch(); # get users data                          if($user["username"]==$username)             {                 $errorMsg[]="Sorry username already exists"; //check condition username already exists             }             else if($user["email"]==$email)             {                 $errorMsg[]="Sorry email already exists"; //check condition email already exists              }             else if($user["phone"]==$phone)             {                 $errorMsg[]="Sorry, the phone number already exists"; //check condition email already exists              }             else if(!isset($errorMsg)) //check no "$errorMs g" show then continue             {                 $new_password = password_hash($password, PASSWORD_DEFAULT); //encrypt password using password_hash()                             // insert form input into database                 $stmt= $pdo->prepare("INSERT INTO users (firstname, lastname, username, gender, password, email, birthday, phone, userimage) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)")->execute($data);                             // find out user's ID                $stmt = $pdo->query("SELECT LAST_INSERT_ID() AS user_id");                $user_id = $stmt[0]["user_id"];                             // redirect to list users page                header("Location: userinfo.php");             }          }                 catch(PDOException $e)             {                 echo $e->getMessage();             }                 } }         // render the header template         include("templates/header.php");                  // render add user template         include("templates/register-form.php");             // render the footer template        include("templates/footer.php"); ?> 

I have the following, relevant code in functions.php, which is called by the config.php:

// validate user input function student_input($data) {     $data = trim($data);     $data = stripslashes($data);     $data = htmlspecialchars($data);     return $data; } 

Another thing: how do I print the errors on the register-form.php right below any existing error’s input field?

register-form.php:

<br> <br> <h1>Register</h1> <br> <form enctype="multipart/form-data" action="register.php" method="post">     <fieldset>         <div class="form-group">             <label>First Name:</label><span class ="error">*</span> <input autofocus class="form-control" name="firstname" placeholder="First Name" type="text"/>             <span class = "error"><?php //echo $errorMsg["firstname"];?></span>         </div>         <div class="form-group">             <label>Last Name:</label><span class ="error">*</span> <input class="form-control" name="lastname" placeholder="Last Name" type="text"/><br />             <span class = "error"><?php //echo $errorMsg["lastname"];?></span>         </div>         <div class="form-group">             <label>Username:</label><span class ="error">*</span> <input class="form-control" name="username" type="text"/><br />             <span class = "error"><?php //echo $errorMsg["username"];?></span>         </div>         <div class="form-group">             <label>Gender:</label><span class ="error">*</span> <select class="form-control" name="gender" value="gender">                 <option value="">Select your gender</option>                 <option value="Male">Male</option>                 <option value="Female">Female</option>             </select><br />             <span class = "error"><?php //echo $error;?></span>         </div>         <div class="form-group">             <label>Password:</label><span class ="error">*</span> <input class="form-control" name="password" type="password"/ autocomplete="off"><br />             <span class = "error"><?php //echo $error;?></span>         </div>         <div class="form-group">             <label>Confirm Password:</label><span class ="error">*</span> <input class="form-control" name="confirmation" type="password"/><br />             <span class = "error"><?php //echo $error;?></span>         </div>         <div class="form-group">             <label>Email:</label><span class ="error">*</span> <input class="form-control" name="email" placeholder="Email" type="text"/><br />             <span class = "error"><?php //echo $error;?></span>         </div>         <div class="form-group">             <label>Phone:</label><span class ="error">*</span> <input class="form-control" name="phone" placeholder="Phone" type="tel" min="10" max="11"/><br />             <span class = "error"><?php //echo $error;?></span>         </div>         <div class="form-group">             <label>Date of Birth:</label><span class ="error"></span> <input class="form-control" name="birthday" placeholder="birthday" type="date" /><br />             <span class = "error"><?php //echo $error[birthday];?></span>         </div>         <div class="form-group">             <label>Passport Photo:</label><input class="form-control" name="userimage" id="fileimage" placeholder="Your Photo" type="file"/>         </div>         <div class="form-group">             <button type="submit" class="btn btn-default" name="Register" value="Register">Register</button>         </div>     </fieldset> </form> <div>     or <a href="login.php">Login</a> </div> <br/> <br> <br>