scaffolding error in cakephp 1.3

i've just started to work on cakephp i've just created the models and in the controller i just have 2 lines

class BlogController extends AppController{
var $name='BlogController';
var $scaffold;
}

i'm getting this error in the view

Undefined property:  BlogController::$primaryKey [CORE/cake/libs/controller/scaffold.php, line 182]开发者_StackOverflow社区
Undefined property:  BlogController::$displayField [CORE/cake/libs/controller/scaffold.php, line 183]

yes what could be the problem thanx in advance

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i figured it out in the name variable i added controller which is not requied and sorry for asking such a dumb question