Translate MYSQL to PDO [closed] - php

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so i tried to convert a little bit of MYSQL to the new PDO;
$u_check = mysql_query("SELECT username FROM users WHERE username='un'");
$check = mysql_num_rows($u_check);
if($check == 0){
echo "Do this";
}
How i did it in PDO:
$u_check = $databaseConnection->prepare("SELECT username FROM users WHERE :username = '$un'");
$check = $databaseConnection->query($u_check);
if($check == 0){
echo "do stuff"
}
But as expeced i get an error:
Warning: PDO::query() expects parameter 1 to be string, object given
in F:\xampp\htdocs\SocialMedia\first\index.php on line 27
Line 27: $check = $databaseConnection->query($u_check);
I have no idea how to get the same result in PDO
Thanks in advance for the help!
EDIT 1:
I have this now:
if($reg) {
if($em==$em2){
$u_check = $databaseConnection->prepare("SELECT username FROM users WHERE :username = '$un'");
$u_check->bind_param("s", "un");
$result = $u_check->execute();
if($result){
echo "hoi";
}
}
}
gives me:
Fatal error: Call to undefined method PDOStatement::bind_param() in
F:\xampp\htdocs\SocialMedia\first\index.php on line 26
EDIT 2: my code at the moment;
<?php include("inc/header.inc.php");?>
<?php
$reg = $_POST['reg'];
$fn = "";
$ln = "";
$un = "";
$em = "";
$em2 = "";
$pswd = "";
$pswd2 = "";
$d = "";
$fn = strip_tags($_POST['fname']);
$ln = strip_tags($_POST['lname']);
$un = strip_tags($_POST['uname']);
$em = strip_tags($_POST['email']);
$em2 = strip_tags($_POST['email2']);
$pswd = strip_tags($_POST['password']);
$pswd2 = strip_tags($_POST['password2']);
$d = date("d-m-Y");
if($reg) {
if($em==$em2){
$u_check = $databaseConnection->prepare("SELECT username FROM users WHERE username= :username");
$u_check->bindParam(':username', $un);//un is the given username that user types
$u_check->execute();
$check = $u_check->rowCount();
if($check > 0){
if($fn&&$ln&&$un&&$em&&$em2&&$pswd&&$pswd2){
if($pswd==$pswd2){
if(strlen($un)>25||strlen($fn)>25||strlen($ln)>25){
echo "Maximum characters is 25!";
}else{
if(strlen($pswd)>30||strlen($pswd)<5){
echo "Your pass must be between 5 and 30 characters!";
}else{
$pswd = md5($pswd);
$pswd2 = md5($pswd2);
$query = $databaseConnection->prepare("INSERT INTO users (username, first_name, last_name, email, password, sign_up_date, activated) VALUES (:un, :fn, :ln, :em, :pswd, :d, '0')");
$query->execute();
die("<h2>Welcome to Profiles</h2>Login to your account to get started...");
}
}
}
}
}else{
echo "Already exists!";
}
}
}
?>
So, now i get the message "Already exists!" everytime,
Altho the setup itself does not work, its not putting the stuff from the form in ....
EDIT 3
I get this:
Parse error: syntax error, unexpected '}' in
F:\xampp\htdocs\SocialMedia\first\index.php on line 50 which is line
if($pswd!=$pswd2){
$errors[] .= 'Passwords are not the same';
}elseif(strlen($pswd)>30||strlen($pswd)<5){
$errors[] .='Your pass must be between 5 and 30 characters!'
}else{
$pswd_md = md5($pswd);
}
which is this line:
}else{

Answer 1

Your code is wrong...Try this one:
<?php include("inc/header.inc.php"); ?>
<?php
function display_errors($errors){
$display = '<ul>';
foreach ($errors as $error){
$display .= '<li>'.$error.'</li>';
}
$display .= '</ul>';
return $display;
}
$reg = $_POST['reg'];
$fn = "";
$ln = "";
$un = "";
$em = "";
$em2 = "";
$pswd = "";
$pswd2 = "";
$d = "";
if(isset($reg)) {
$errors = array();
$fn = strip_tags($_POST['fname']);
$ln = strip_tags($_POST['lname']);
$un = strip_tags($_POST['uname']);
$em = strip_tags($_POST['email']);
$em2 = strip_tags($_POST['email2']);
$pswd = strip_tags($_POST['password']);
$pswd2 = strip_tags($_POST['password2']);
$d = date("d-m-Y");
$required = array('fname','lname','uname','email','email2','password','password2');
foreach($required as $field){
if($_POST[$field] == ''){
$errors[] .= $field. ' is required';
}
}
if(strlen($un)>25||strlen($fn)>25||strlen($ln)>25){
$errors[] .= "Maximum characters is 25!";
}
if($pswd!=$pswd2){
$errors[] .= 'Passwords are not the same';
}elseif(strlen($pswd)>30||strlen($pswd)<5){
$errors[] .='Your pass must be between 5 and 30 characters!'
}else{
$pswd_md = md5($pswd);
}
if($em != $em2){
$errors[] .= 'Emails are not the same';
}
$u_check = $databaseConnection->prepare("SELECT username FROM users WHERE username= :username");
$u_check->bindParam(':username', $un);//un is the given username that user types
$u_check->execute();
$check = $u_check->rowCount();
if($check > 0){
$errors[] .= 'User Exists. Choose another username';
}
if(!empty($errors)){
echo display_errors($errors);
}else{
$ac = 0;
$query = $databaseConnection->prepare("INSERT INTO users (username, first_name, last_name, email, password, sign_up_date, activated) VALUES (:un, :fn, :ln, :em, :pswd, :d, :ac)");
$query->bindParam(':un',$un);
$query->bindParam(':fn',$fn);
$query->bindParam(':ln',$ln);
$query->bindParam(':em',$em);
$query->bindParam(':pswd',$pswd_md);
$query->bindParam(':d',$d);
$query->bindParam(':ac',$ac);
$query->execute();
}
if($query){
//INSERT SUCCESS
echo 'Success';
}else{
echo 'Failed;'
}
}
?>

Answer 2

It is because for query() you need a String, but you give an object (Look: http://php.net/manual/de/pdo.query.php)
There is an example:
<?php
function getFruit($conn) {
$sql = 'SELECT name, color, calories FROM fruit ORDER BY name';
foreach ($conn->query($sql) as $row) {
print $row['name'] . "\t";
print $row['color'] . "\t";
print $row['calories'] . "\n";
}
}
?>
If you want to use prepare have a look at: http://php.net/manual/de/pdo.prepare.php
You have to use $var->execute(array($var1, $var2));

Answer 3

If I see correctly you want to check if the given username exists in the database. Call ->execute() on the prepared statement and use rowCount() on the returned object to get the number of results.
Check the documentation for more info: PDO rowCount and PDO Prepare
But if you really only need the number of rows where the username is the given username (since you select username and use it in the condition also) you can simply select the number:
SELECT count(username) FROM users GROUP BY username HAVING username = $username