config.php

<?php
session_start();
$conn = mysqli_connect("localhost", "root", "", "hack");
if (mysqli_connect_errno()) {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

function checkQuery($exe, $message)
{
  if ($exe) {
    echo "<script>alert('" . $message . "');</script>";
  } else {
    echo "<script>alert('Please Retry')</script>";
  }
}

function addUser($uname, $pass)
{
  global $conn;
  $qry = "INSERT into user values('','$uname','$pass','Teacher')";
  $exe = mysqli_query($conn, $qry);
  checkQuery($exe, 'Inserted');
}

function addSubject($sname, $subcode, $sem, $dept)
{
  global $conn;
  $qry = "INSERT into user values('','$sname','$subcode','$sem','$dept)";
  $exe = mysqli_query($conn, $qry);
  checkQuery($exe, 'Inserted');
}

function addDepartment($deptName)
{
  global $conn;
  $qry = "INSERT into departments values('','$deptName')";
  $exe = mysqli_query($conn, $qry);
  checkQuery($exe, 'Inserted');
}

function addPaper($subCode, $paperId, $maxm, $sem, $year)
{
  global $conn;
  $qry = "INSERT into paper values('','$subCode','$paperId','$maxm','$sem','$year','0')";
  $exe = mysqli_query($conn, $qry);
  checkQuery($exe, 'Inserted');
}

function addQuestions($paperId, $question, $part, $marks)
{
  global $conn;
  $qry = "INSERT into questions values('','$paperId', '$question', '$part', '$marks')";
  $exe = mysqli_query($conn, $qry);
  checkQuery($exe, 'Inserted');
}

function login($username, $passwd)
{
  global $conn;
  $sql = 'SELECT * FROM user WHERE uname = "' . $username . '" and password ="' . $passwd . '"';
  $result = mysqli_query($conn, $sql);
  $row = mysqli_fetch_array($result);
  $count = mysqli_num_rows($result);
  if ($count == 1) {
    $_SESSION['userName'] = $row[1];
    $_SESSION['userType'] = $row[3];
    header("location: index.php");
  } else {
    echo "<script>console.log('Your Login Name or Password is invalid')</script>";
  }
}

function getData($table, $offset)
{
  global $conn;
  $qry = "SELECT * FROM $table";
  $exe = mysqli_query($conn, $qry);
  $array = array(array());
  $i = 0;
  while ($cont = mysqli_fetch_array($exe)) {
    for ($j = 0; $j <= $offset - 1; $j++) {
      $array[$i][$j] = $cont[$j];
    }
    $i++;
  }
  return $array;
}
$papersAll = getData('paper', 7);
$departments = getData('departments', 3);
$subjects = getData('subjects', 5);

function getURL($n)
{
  $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
  $randomString = '';

  for ($i = 0; $i < $n; $i++) {
    $index = rand(0, strlen($characters) - 1);
    $randomString .= $characters[$index];
  }

  return $randomString;
}

function getSubjectName($code)
{
  global $subjects;
  foreach ($subjects as $subject) {
    if ($subject[2] == $code) {
      return $subject[1];
    }
  }
}

function setLive($paperId, $start, $end, $date)
{
  global $conn;
  $qry = "INSERT into onair values('','$paperId','$start','$end','$date','" . getURL(10) . "')";
  $exe = mysqli_query($conn, $qry);
  if ($exe) {
    $qry = "UPDATE paper SET islive='1' WHERE `paper_id`='$paperId'";
    $exe = mysqli_query($conn, $qry);
  }
  checkQuery($exe, 'Exam Set Live');
}