PHP的数据库中插入字符'不工作

Question

我的代码无法将字符'插入数据库，这是用户插入像我这样的单词时出现的问题

<?php 
if(!isset($_SESSION)) 
{ 
    session_start(); 
} 
$db = mysqli_connect('localhost', 'root', '', 'generator');

//initialized variables
$staffname="";
$position="";
$date="";
$report="";
$id = 0;

//call for the form information
    $staffname = $_POST['staffname'];
    $position = $_POST['position'];
    $report =$_POST['report'];
    $staffid = $_POST['staffid'];
    $user_type = $_POST['user_type'];
    date_default_timezone_set('Asia/Kuala_Lumpur'); 
    $date = date('d/m/Y h:i:s a', time()); 



    //insert into database. 
    mysqli_query($db, "INSERT INTO daily_report (staffname,position, 
 date, report, staffid , user_type)
    VALUES('$staffname','$position', '$date', '$report', '$staffid', 
'$user_type')");
    $_SESSION['message'] = "Your report have been submitted"; 
    header('location: daily_report.php');
?>   

我能够在数据库中插入字符'