# Validate field not in model?

**URL:** <https://www.ruby-forum.com/t/validate-field-not-in-model/161523>\
**Category:** Rails\
**Created:** [February 27, 2009, 3:51am UTC](https://www.ruby-forum.com/t/validate-field-not-in-model/161523 "2009-02-27T03:51:05Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![mikec](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mikec](https://www.ruby-forum.com/u/mikec)\
**Post date:** [February 27, 2009, 3:51am UTC](https://www.ruby-forum.com/t/validate-field-not-in-model/161523/1 "2009-02-27T03:51:05Z")

</div>

I want to validate a field in my form that’s not an attribute in the  
model. How do I do this?

---

<div class="post-metadata">

**Author:** ![mikec](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mikec](https://www.ruby-forum.com/u/mikec)\
**Post date:** [February 27, 2009, 6:53am UTC](https://www.ruby-forum.com/t/validate-field-not-in-model/161523/2 "2009-02-27T06:53:47Z")

</div>

define it as a getter and setter.

On Fri, Feb 27, 2009 at 10:49 AM, Mike C [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I want to validate a field in my form that’s not an attribute in the  
> model. How do I do this?
> 
> >

–  
TWRUG Blog:  
[http://blog.rubyonrails.org.tw](http://blog.rubyonrails.org.tw)

CFC on Rails:

> **[CFC on Rails](http://zusocfc.blogspot.com)**
>
> 火車請別撞我

Only two surfaces of a box:  
[http://blog.pixnet.net/zusocfc](http://blog.pixnet.net/zusocfc)

---

<div class="post-metadata">

**Author:** ![mikec](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mikec](https://www.ruby-forum.com/u/mikec)\
**Post date:** [February 27, 2009, 7:11am UTC](https://www.ruby-forum.com/t/validate-field-not-in-model/161523/3 "2009-02-27T07:11:20Z")

</div>

Ok, I did it. But in the model I have validates\_presence\_of, and even  
though the field is filled, I keep getting the blank error.

---

<div class="post-metadata">

**Author:** ![mikec](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mikec](https://www.ruby-forum.com/u/mikec)\
**Post date:** [February 27, 2009, 9:20am UTC](https://www.ruby-forum.com/t/validate-field-not-in-model/161523/4 "2009-02-27T09:20:12Z")

</div>

Nevermind, getter was returning a user object instead of a string.  
fixed. 🙂

---

<div class="post-metadata">

**Author:** ![mikec](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/977dab/32.png) [@mikec](https://www.ruby-forum.com/u/mikec)\
**Post date:** [February 27, 2009, 10:03am UTC](https://www.ruby-forum.com/t/validate-field-not-in-model/161523/5 "2009-02-27T10:03:36Z")

</div>

Hi Mike. Can you share the code snippet for the getter and setter  
methods  
you used, thanks.