# Auto set value for a model field

**URL:** <https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901>\
**Category:** Rails\
**Created:** [October 10, 2007, 11:53pm UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901 "2007-10-10T23:53:42Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 10, 2007, 11:53pm UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/1 "2007-10-10T23:53:42Z")

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Hello,

I have a model - Post with datetime field \<added\_at\>. I need to set this  
value to time when in created or when it updated automatically.

Thanks

---

<div class="post-metadata">

**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 11, 2007, 1:18am UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/2 "2007-10-11T01:18:36Z")

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> I have a model - Post with datetime field \<added\_at\>. I need to set this  
> value to time when in created or when it updated automatically.

Why not use the fields created\_at and updated\_at and let Rails do this  
for  
you?

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<div class="post-metadata">

**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 11, 2007, 8:56am UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/3 "2007-10-11T08:56:01Z")

</div>

> Why not use the fields created\_at and updated\_at and let Rails do this  
> for  
> you?

Hello,

Thanks fro reply.

How to do it?

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<div class="post-metadata">

**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 11, 2007, 11:00am UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/4 "2007-10-11T11:00:07Z")

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Hi Igor

Philip is right.Just add  
created\_at or created\_on  
updated\_at or updated\_on

in your table.

That’s it 🙂

On Oct 11, 2:56 pm, “Igor K.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

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<div class="post-metadata">

**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 11, 2007, 11:16am UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/5 "2007-10-11T11:16:01Z")

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I tried it - and i think i can use onle updated\_at field.

Thanks

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<div class="post-metadata">

**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 11, 2007, 11:09am UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/6 "2007-10-11T11:09:49Z")

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> Philip is right.Just add  
> created\_at or created\_on  
> updated\_at or updated\_on
> 
> in your table.

But I don’t need a two columns for this. I want to have one field that  
contain datetime when it last time modified of created.

Thanks for reply

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<div class="post-metadata">

**Author:** ![demoversion](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/4491bb/32.png) [@demoversion](https://www.ruby-forum.com/u/demoversion)\
**Post date:** [October 11, 2007, 11:36am UTC](https://www.ruby-forum.com/t/auto-set-value-for-a-model-field/116901/7 "2007-10-11T11:36:33Z")

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Hi Igor

Being opinionated,Rails had already decided on auto-updating on create  
and on update separately 🙂

On Oct 11, 5:16 pm, “Igor K.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)