values not inserting into db while using mysqli - php

Question

I am using mysqli to try and retrieve the teacher's username and then insert all of the values into the dataabse. The problem though is that nothing is being inserted into the database.
I am getting no errors in my error report so I think I am just doing something wrong when it comes to inserting values into the database using mysqli but I am not sure what. Can anybody give me any pointers on why it is not inserting values into the db?
Below is the code:
$username="xxx";
$password="xxx";
$database="mobile_app";
$mysqli = new mysqli("localhost", $username, $password, $database);
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
die();
}
$sql = "SELECT TeacherId FROM Teacher WHERE (TeacherUsername = ?)";
$stmt=$mysqli->prepare($sql);
// You only need to call bind_param once
$stmt->bind_param("s",$_SESSION['teacherusername']);
$stmt->execute();
$record = $stmt->fetch();
$teacherid = $record['TeacherId'];
if($_SERVER['REQUEST_METHOD'] == 'POST')
{
$time = str_replace(array(' Hrs ', ' Mins ', ' Secs'), array(':', ':', ''), $_SESSION['durationChosen']);
$insertsql = "INSERT INTO Session (SessionId, SessionTime, SessionDate, SessionWeight, SessionDuration, TotalMarks, ModuleId, TeacherId, Room)
VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";
$insert=$mysqli->prepare($insertsql);
$insert->bind_params("sssssssss", $sessid, $_SESSION['timeChosen'], $sessdate,
$_SESSION['textWeight'], $time, $_SESSION['textMarks'],
$_SESSION['module'], $teacherid, $_SESSION['rooms']);
for ($i = 1, $n = $_SESSION['sessionNum']; $i <= $n; ++$i) {
$sessid = $_SESSION['id'] . ($n == 1 ? '' : $i);
$sessdate = date("Y-m-d", strtotime($_SESSION['dateChosen']));
$insert->execute();
}
$insert->close();
}

Answer 1

Try to debug this thing line by line:
set your error reporting to error_reporting(E_ALL); in php file or error_reporting = E_ALL in php ini
does the db connection work ?
echo the sql query before using it
it the query seems to be correct: rebuild it to ONE value and rebuild it step by step to find out where's the error