CODEIGNITER call to a member function num rows on boolean

Please i have an issue with codeigniter. when i try to log here is the result:

Fatal error: Call to a member function num_rows() on boolean in D:\xampp\htdocs\procurementSys\application\models\login_model.php on line 19.

Below tho code of the relative file:

Code:

<?php


 class Login_model extends CI_Model {

//this function checks whether the username and the password is in the database or not
public function check_login($username, $password){

   $this->db->select('username, password, status');
   $array = array('username' => $username, 'password' => sha1($password),'status' => 'active');
   $this->db->where($array);
   $query = $this->db->get('user');

   if($query->num_rows() == 1) // if the affected number of rows is one---LINE 19---
   {
       return true;
   }
   else
   {
       return false;
   }
}

//this function returns the status of the user to be used in authentication
public function user_login_data($username, $password){

   $this->db->select('status');
   $array = array('username' => $username, 'password' => sha1($password));
   $this->db->where($array);
   $query = $this->db->get('user');

   if($query->num_rows() == 1) // if the affected number of rows is one
   {
        $row = $query->row();
        return $row->status;
   }
 //        else
 //        {
 //            return false;
 //        }
}


public function user_role($username){ // this function gets the user's role from the database
    $this->db->select('role');
    $this->db->where('username', $username);
    $query = $this->db->get('user');
    $row = $query->row(0);

    return $row->role;
}

public function department($username){ // this function gets the user's department from the database
    $this->db->select('department');
    $this->db->where('username', $username);
    $query = $this->db->get('user');
    $row = $query->row(0); // returns the first row with an array of objects that is stored in the row variable

    return $row->department;
}

public function get_user_id($username){ // this function gets the user's department from the database
    $this->db->select('userID');
    $this->db->where('username', $username);
    $query = $this->db->get('user');
    $row = $query->row(0); // returns the first row with an array of objects that is stored in the row variable

    return $row->userID ;
}

public function fullname($username){
    $this->db->select('firstName, secondName');
    $this->db->where('username', $username);
    $query = $this->db->get('user');
    $row = $query->row(0);
    return $row;

 //            foreach($query->result() as $row) // returns the query as an array of objects
 //           {
 //                $data[] = $row; // equates the array of objects to an array variable
 //           }
 //        
 //           return $data;
  // }
}

}

?>

I kept searching for a solution and found nothing. CI VERSION 2.1.2    thanks

Hi

Change Below Code:

PHP Code:

if($query->num_rows() == 1) // if the affected number of rows is one---LINE 19---
   {
       return true;
   }
   else
   {
       return false;
   } 


To:

PHP Code:

if($query !== FALSE && $query->num_rows() == 1) // if the affected number of rows is one---LINE 19---
   {
       return true;
   }
   else
   {
       return false;
   }