# Updating updated\_at column on a belongs\_to

**URL:** <https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373>\
**Category:** Rails\
**Created:** [December 18, 2009, 6:17pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373 "2009-12-18T18:17:44Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![bingobob](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e480ec/32.png) [@bingobob](https://www.ruby-forum.com/u/bingobob)\
**Post date:** [December 18, 2009, 6:17pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373/1 "2009-12-18T18:17:44Z")

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I have a…

class Resort \< ActiveRecord::Base  
has\_many :photos, :order =\> “position”  
end

class Photo \< ActiveRecord::Base  
belongs\_to :resort  
end

What I have a problem with is that if I update a photo I really need the  
updated\_at attribute on the Resort to change as well, how do I do this?

Thanks

bb

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<div class="post-metadata">

**Author:** ![bingobob](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e480ec/32.png) [@bingobob](https://www.ruby-forum.com/u/bingobob)\
**Post date:** [December 18, 2009, 6:51pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373/2 "2009-12-18T18:51:38Z")

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bingo bob wrote:

> I have a…
> 
> class Resort \< ActiveRecord::Base  
> has\_many :photos, :order =\> “position”  
> end
> 
> class Photo \< ActiveRecord::Base  
> belongs\_to :resort  
> end
> 
> What I have a problem with is that if I update a photo I really need the  
> updated\_at attribute on the Resort to change as well, how do I do this?

Use an after\_update callback on Photo.

> Thanks
> 
> bb

Best,  
–Â  
Marnen Laibow-Koser  
[http://www.marnen.org](http://www.marnen.org)  
removed\_email\_address@domain.invalidÂ

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<div class="post-metadata">

**Author:** ![bingobob](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e480ec/32.png) [@bingobob](https://www.ruby-forum.com/u/bingobob)\
**Post date:** [December 18, 2009, 7:04pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373/3 "2009-12-18T19:04:10Z")

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Ok.

Could you kindly clarify?

In my Photo model?

What would I put?

after\_update… Do something with Resort.

Bb

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<div class="post-metadata">

**Author:** ![bingobob](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e480ec/32.png) [@bingobob](https://www.ruby-forum.com/u/bingobob)\
**Post date:** [December 18, 2009, 8:09pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373/4 "2009-12-18T20:09:14Z")

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bingo bob wrote:

> Ok.
> 
> Could you kindly clarify?
> 
> In my Photo model?
> 
> What would I put?
> 
> after\_update… Do something with Resort.

Right. Go read about ActiveRecord callbacks and all will become clear.

> Bb

Best,  
–Â  
Marnen Laibow-Koser  
[http://www.marnen.org](http://www.marnen.org)  
removed\_email\_address@domain.invalidÂ

---

<div class="post-metadata">

**Author:** ![bingobob](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e480ec/32.png) [@bingobob](https://www.ruby-forum.com/u/bingobob)\
**Post date:** [December 18, 2009, 8:57pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373/5 "2009-12-18T20:57:12Z")

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Marnen Laibow-Koser wrote:

> bingo bob wrote:
> 
> > Ok.
> > 
> > Could you kindly clarify?
> > 
> > In my Photo model?
> > 
> > What would I put?
> > 
> > after\_update… Do something with Resort.
> 
> Right. Go read about ActiveRecord callbacks and all will become clear.

And, assuming you’re using a recent version or Rails you can ‘touch’  
your models:

[http://afreshcup.com/home/2009/4/19/touch-your-active-record-instances.html](http://afreshcup.com/home/2009/4/19/touch-your-active-record-instances.html)

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<div class="post-metadata">

**Author:** ![bingobob](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/e480ec/32.png) [@bingobob](https://www.ruby-forum.com/u/bingobob)\
**Post date:** [December 20, 2009, 4:48pm UTC](https://www.ruby-forum.com/t/updating-updated-at-column-on-a-belongs-to/180373/6 "2009-12-20T16:48:39Z")

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Just to update and help anyone else.  
As is mentioned above I simply touched and it simply worked.  
Rails is beautiful sometimes :-).

class Photo \< ActiveRecord::Base  
belongs\_to :resort, :touch =\> true  
end

Thanks all.