php - Getting Fatal error: Call to a member function query() on a non object error while including database details twice -

i have 3 files in program database.php ,index.php,functions.php when click next button of dashboard.php file shows these 2 errors.

notice: undefined variable: conn in c:\wamp\www\quiz\functions.php on line 144

fatal error: call member function query() on non-object in c:\wamp\www\quiz\functions.php on line 41

line number 144 $result = $conn->query($sql); when replace include_once('database.php');line of getquizes_answer1() function content of database.php file works fine. there can clarify why happening this?

this how functions.php file looks like

function getquizes($quizno) {     if($quizno==null)     {         $quizno=0;     }     require('database.php');     $sql = "select * quiz limit ".$quizno.",1";     $result = $conn->query($sql);     while($row=$result->fetch_assoc())     {         echo $row['question'];     }     $quizno++;     $sql = "select * quiz";     $result = $conn->query($sql);     $rowcount=mysqli_num_rows($result);      if($quizno>=$rowcount)     {         $quizno=0;     }     return $quizno; }  function getquizes_answer1($quizno) {     include_once('database.php');     if($quizno!=0)     {         $quizno--;     }     $sql = "select * quiz limit ".$quizno.",1";     $result = $conn->query($sql);     while($row=$result->fetch_assoc())     {         echo $row['answer1'];     }     $sql = "select * quiz";     $result = $conn->query($sql);     $rowcount=mysqli_num_rows($result);     if($quizno>=$rowcount)     {         $quizno=0;     } $conn->close(); } 

this how dashboard.php file looks like

<?php     $i = isset($_session['next']) ? $_session['next'] : null;     if(isset($_post['next']))     {         $i = getquizes($i);         $_session['next'] = $i;  ?>  <div class="answers_block">      <table>                 <tr>                     <td><?php getquizes_answer1($i);?></td>                 </tr>      </table>  </div>      <?php      }      ?>        <form method="post" action="<?php echo $_server['php_self']; ?>">            <input name="next" value="next" type="submit" />        </form> 

my database.php file looks this

<?php $servername = "localhost"; $username = "root"; $password = ""; $database="quiz_db"; // create connection $conn = new mysqli($servername, $username, $password, $database); // check connection if ($conn->connect_error) { die("connection failed: " . $conn->connect_error); }  

the problem is, connection handler $conn not available in scope of function. either use global or pass connection handler argument function.

method(1):

function getquizes($quizno){     global $conn;      // code }  function getquizes_answer1($quizno){     global $conn;      // code } 

method(2):

function getquizes($conn, $quizno){      // code  }  function getquizes_answer1($conn, $quizno){      // code  }