PDO Username validation if already exists - php

Question

I have a problem with register form.My form works properly but whenever i try to insert username that already exists it doesn't shows any error.
here is my php register file:
<?php
$servername = "localhost";
$username = "root";
$password = "";
try {
$conn = new PDO("mysql:host=$servername;dbname=dblogin", $username, $password);
// set the PDO error mode to exception
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
if (isset($_POST['submit'])) {
$user_name = $_POST['user_name'];
$user_email = $_POST['user_email'];
$user_pass = $_POST['user_pass'];
$hash = password_hash($user_pass, PASSWORD_DEFAULT);
$stmt = $con->prepare("SELECT user_name FROM users WHERE user_name = :user_name");
if($stmt->rowCount() > 0){
echo "exists!";
}
else{
$insert = $conn->prepare("INSERT INTO users (user_name,user_email,user_pass) values(:user_name,:user_email,:user_pass)");
$insert->bindparam(':user_name',$user_name);
$insert->bindparam(':user_email',$user_email);
$insert->bindparam(':user_pass',$hash);
$insert->execute();
}
}
catch(PDOException $e)
{
echo "connection failed";
}
?>
Thanks for your support

Answer 1

You are not executing the select statement. You need to bind params and execute the select statement, try this after the select statemnt.
$stmt->bindparam(':user_name',$user_name);
$stmt->execute();

Answer 2

public function usernameCheck($username)
{
$sql = "SELECT * FROM $this->table where username = :username";
$query = $this->pdo->prepare($sql);
$query->bindValue(':username', $username);
$query->execute();
if ($query->rowCount() > 0) {
return true;
} else {
return false;
}
}
use this one in your project hope it will work... :)

Answer 3

missing } in if statement
if (isset($_POST['submit'])) {
$user_name = $_POST['user_name'];
$user_email = $_POST['user_email'];
$user_pass = $_POST['user_pass'];
$hash = password_hash($user_pass, PASSWORD_DEFAULT);
$stmt = $con->prepare("SELECT user_name FROM users WHERE user_name = :user_name");
if($stmt->rowCount() > 0){
echo "exists!";
}
}else{
}

Answer 4

I notice 4 things (2 of which have been mentioned by others):
First and smallest is you have a spelling error ($con instead of $conn) - don't worry it happens to the best of us - in you first $stmt query which means your select-results becomes NULL instead of 0 - so you rowCount find that it is not over 0 and moves on without your error message
Second you forgot to bind and execute the parameters in your first $stmt query which gives the same result for your rowCount results
Third always clean your variables even when using prepared statements - at a bare minimum use
$conn->mysql_real_escape_string($variable);
and you can with advantage use
htmlspecialchars($variable);
And fourth since you are not doing anything with the database (other than looking) you could simplify your code by simply writing:
$stmt = $conn->query("SELECT user_name FROM users WHERE user_name = '$user_name' LIMIT 1")->fetch();
as I said - no need to bind or execute in the first query
and as a general rule - don't use rowCount - ever - if you have to know the number of results (and in 99% of cases you don't) use count(); but if you as here just want to know if anything at all was found instead use:
if ( $stmt ) {
echo "exists!";
} else {
// insert new user as you did
}
Edit:
Also - as a side note - there are a few things you should consider when you initially create your connection...
Ex:
// Set variables
$servername = "localhost";
$username = "***";
$password = "***";
$database = "***";
$charset = 'utf8'; // It is always a good idea to also set the character-set
// Always create the connection before you create the new PDO
$dsn = "mysql:host=$servername;dbname=$database;charset=$charset";
// Set default handlings as you create the new PDO instead of after
$opt = [
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, // And add default fetch_mode
PDO::ATTR_EMULATE_PREPARES => false, // And ALWAYS set emulate_prepares to false
];
// And now you are ready to create your new PDO
$conn = new PDO($dsn, $username, $password, $opt);
Just a suggestion... happy trails