# How to declare model classes in Application.rb

**URL:** <https://www.ruby-forum.com/t/how-to-declare-model-classes-in-application-rb/156498>\
**Category:** Ruby\
**Created:** [December 29, 2008, 7:20am UTC](https://www.ruby-forum.com/t/how-to-declare-model-classes-in-application-rb/156498 "2008-12-29T07:20:49Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![vikas](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/ac91a4/32.png) [@vikas](https://www.ruby-forum.com/u/vikas)\
**Post date:** [December 29, 2008, 7:20am UTC](https://www.ruby-forum.com/t/how-to-declare-model-classes-in-application-rb/156498/1 "2008-12-29T07:20:49Z")

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Hello all,  
I am new to ruby development.  
I created a simple online book store Application.  
but when i select book & click on ‘add to cart’ it gives me error

“undefined method `model’ for ApplicationController:Class”

class ApplicationController \< ActionController::Base

model :cart  
model :line\_item

end

cart & line\_item are two model classes.  
I am storing the model cart in session  
I’m using rails 2.2 version  
So what’s going wrong?  
please help me to solve this problem.

Vikas

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<div class="post-metadata">

**Author:** ![vikas](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/ac91a4/32.png) [@vikas](https://www.ruby-forum.com/u/vikas)\
**Post date:** [December 29, 2008, 8:53am UTC](https://www.ruby-forum.com/t/how-to-declare-model-classes-in-application-rb/156498/2 "2008-12-29T08:53:52Z")

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On Dec 28, 2008, at 22:20 , Vikas G. wrote:

> Hello all,  
> I am new to ruby development.  
> I created a simple online book store Application.  
> but when i select book & click on ‘add to cart’ it gives me error

please ask these questions on the ruby on rails mailing list.