An uncaught Exception was encountered

Type: Error

Message: Call to a member function real_escape_string() on bool

Filename: /home/studywhm/public_html/system/database/drivers/mysqli/mysqli_driver.php

Line Number: 350

Backtrace:

File: /home/studywhm/public_html/application/models/Examcategory_model.php
Line: 8
Function: where

File: /home/studywhm/public_html/application/core/MY_Controller.php
Line: 121
Function: getExamCatgeories

File: /home/studywhm/public_html/application/core/MY_Controller.php
Line: 254
Function: __construct

File: /home/studywhm/public_html/application/modules/questionbank/controllers/Welcome.php
Line: 4
Function: __construct

File: /home/studywhm/public_html/index.php
Line: 300
Function: require_once