Item doesn't get removed from database - php

Question

I've been looking for hours atm but I can't seem to delete an item from my database. The $id is from $_GET['id']
<?php
$hostdb = "localhost";
$userdb = "root";
$pwdb = "";
$namedb = "cloud";
$dbCon = mysqli_connect($hostdb, $userdb, $pwdb, $namedb);
if(!$dbCon){
die("CONNECTION FAILED");
}
?>
Call to action remove button. Redirect to customers.php
<form action="customers.php" method="POST">
<button type="submit" name="remove" class="btn btn-sm btn-danger"><i class="glyphicon glyphicon-remove-circle"></i> Remove</button>
</form>
<?php
if(isset($_POST['remove'])) {
include("php/remove.php");
removeCustomer($id);
}
?>
Remove class
<?php
function removeCustomer($id){
include("connect.php");
$query = "DELETE FROM customers WHERE Id='$id'";
echo $id //gives me the right id
if(!mysqli_query($dbCon,$query) === TRUE){
echo "Error while removing customer from the database.";
}
mysqli_close($dbCon);
}
?>
UPDATE
When I redirect to the same page, then it does get removed.
But that's not the right way I suppose.
Ex. When I'm at page customer.php?id=2 and my form redirects to customer.php?id=2 then it's removed.
UPDATE 2 + SOLUTION
I've removed the "action" redirect in my form and it works fine.

Answer 1

There are a few things you can do to tighten up this code and make it more self-diagnostic when it goes wrong.
First, follow the convention on handling the result from mysqli_query(). Just check for the negation.
Secondly, make your error message announce the problem as well as the failure. Also, for troubleshooting's sake, make it announce success.
Thirdly, it's unlikely but possible that you don't have autocommit set. So commit your change immediately after you do the delete.
That will produce this code.
$query = "DELETE FROM customers WHERE Id='$id'";
if(!mysqli_query($dbCon,$query)){
echo "Error while removing customer ($id) from the database: "
. $dbCon->error;
}
else {
echo "Customer ($id) correctly removed from the database.";
}
if (!mysqli_commit($dbCon)) {
echo "Transaction commit failed: " . $dbCon->error;
}
mysqli_close($dbCon);
Finally, use a bind parameter to protect your code against cybercriminals. Then your code will look like this.
$query = "DELETE FROM customers WHERE Id=?";
$stmt = mysqli_prepare($dbCon, $query) || die ($dbCon->error);
mysqli_stmt_bind_param($stmt, 'd', $id) || die ($dbCon->error);
if(!mysqli_stmt_execute($stmt)){
echo "Error while removing customer ($id) from the database: "
. $dbCon->error;
}
mysqli_stmt_close($stmt);
if (!mysqli_commit($dbCon)) {
echo "Transaction commit failed: " . $dbCon->error;
}
mysqli_close($dbCon);
This business with the $stmt looks like a lot of extra work. But it's much safer -- proof against malicious rubbish in your $id variable.

Answer 2

Replace your If condition with this code.
if(mysqli_query($dbCon,$query) == FALSE){
echo "Error while removing customer from the database.";
}
OR
if(mysqli_query($dbCon,$query) != TRUE){
echo "Error while removing customer from the database.";
}
AND
if your Id is int then remove single quote in where condition.