# Polymorphism with created\_at and modified\_at

**URL:** <https://www.ruby-forum.com/t/polymorphism-with-created-at-and-modified-at/148385>\
**Category:** Rails\
**Created:** [September 12, 2008, 12:41pm UTC](https://www.ruby-forum.com/t/polymorphism-with-created-at-and-modified-at/148385 "2008-09-12T12:41:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\
**Post date:** [September 12, 2008, 12:41pm UTC](https://www.ruby-forum.com/t/polymorphism-with-created-at-and-modified-at/148385/1 "2008-09-12T12:41:54Z")

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Hi,

I was wondering what happens, if I use polymorphism in combination  
with created\_at and modified\_at?

Lets say I have 3 models, which all have the attributes created\_at and  
modified\_at, then how will they updated?

Will changes in the child affect the “modified\_at” of the parent?

Will a “child.attribute\_at()” yields the value of the child or the  
parent?

Given the child, how can I read the attribute of the parent?

Fritz