# Creating variable

**URL:** <https://www.ruby-forum.com/t/creating-variable/125823>\
**Category:** Ruby-Forum\
**Created:** [January 12, 2008, 2:07pm UTC](https://www.ruby-forum.com/t/creating-variable/125823 "2008-01-12T14:07:16Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![zaid](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/e95f7d/32.png) [@zaid](https://www.ruby-forum.com/u/zaid)\
**Post date:** [January 12, 2008, 2:07pm UTC](https://www.ruby-forum.com/t/creating-variable/125823/1 "2008-01-12T14:07:16Z")

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Good morning,

I am beginning to develop a ruby part of a web. I  
I have the driver code “book” and I spend their ID in the variable  
Book.current\_book.id, but gives me the following error.

undefined method `current\_book’ for Book:Class

How do I define the variable to my tests?

Thank you