php - Fatal error: Class not found in codeigniter -

i have created model admin_model under application\core directory of code igniter. put basic database operations under it. when try extend models under application\model directory, throws error.

fatal error: class 'admin_model' not found in <path root>/application/models/new_model.php on line 3

should miss configuration?

extending core class

if need add functionality existing library - perhaps add function or 2 - it's overkill replace entire library version. in case it's better extend class. extending class identical replacing class couple exceptions:

the class declaration must extend parent class. new class name , filename must prefixed my_ (this item configurable. see below.). example, extend native model class you'll create file named application/core/my_model.php, , declare class with:

class my_model extends ci_model {  } 

note: if need use constructor in class make sure extend parent constructor:

class my_model extends ci_model {      function __construct()     {         parent::__construct();     } }