# Question regarding form\_for

**URL:** <https://www.ruby-forum.com/t/question-regarding-form-for/93029>\
**Category:** Rails\
**Created:** [April 26, 2007, 6:31pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029 "2007-04-26T18:31:07Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![chell](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/73ab20/32.png) [@chell](https://www.ruby-forum.com/u/chell)\
**Post date:** [April 26, 2007, 6:31pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029/1 "2007-04-26T18:31:07Z")

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Hello,

in my application, I have a new action inside of a controller. I also  
have a view called new.rhtml which contains a form constructed using  
the form\_for method. In the controller’s new action I have an instance  
variable called @story which I assign a new Story object (Story is my  
model) like so:

@story = Story.new(params[:story])

I use form\_for like so:

form\_for :story …

If I change :story to let’s say :abc in both instanced, it still  
works. However, my book says I have to call it :stories so it  
“properly maps with the @story object”. Well, this obviously isn’t the  
case here, as it still works.

Can someone maybe explain it to me?

chell

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<div class="post-metadata">

**Author:** ![chell](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/73ab20/32.png) [@chell](https://www.ruby-forum.com/u/chell)\
**Post date:** [April 26, 2007, 7:11pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029/2 "2007-04-26T19:11:12Z")

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When you say it works, do you mean that the form still displays or  
that the data actually gets saved when you post the form. If the  
later, then it would be good to see the rest of your form code to  
answer your question.

If it’s just that the form is still displayed, then this is just  
because the form helper is not exactly ‘linked’ to the @story  
variable. :story just tells the form helper to firstly, name the  
fields correct (story[name]) and secondly, to put any attributes for  
an existing @story variable in the correct fields. When you put :abc,  
the form helper will look for @abc, see there isn’t one and display  
the form normally.

Hope that helps,

Steve

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<div class="post-metadata">

**Author:** ![chell](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/73ab20/32.png) [@chell](https://www.ruby-forum.com/u/chell)\
**Post date:** [April 26, 2007, 7:15pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029/3 "2007-04-26T19:15:12Z")

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It actually still saves the data! Here’s the controller:

class StoryController \< ApplicationController  
def index  
@story = Story.find(:first, :order =\> ‘RAND()’)  
end  
def new  
@story = Story.new(params[:abc])  
if request.post?  
@story.save  
redirect\_to :action =\> ‘index’  
end

end  
end

And here’s the form itself:

\<% form\_for :story do |f|%\>

name:   
 \<%= f.text\_field :name%\>

link:   
 \<%= f.text\_field :link%\>

\<%= submit\_tag%\>

\<% end %\>

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<div class="post-metadata">

**Author:** ![chell](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/73ab20/32.png) [@chell](https://www.ruby-forum.com/u/chell)\
**Post date:** [April 26, 2007, 8:23pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029/4 "2007-04-26T20:23:18Z")

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Ok - that’s fine. As I said, it’s not that :story links the form to  
the @variable - it’s that it sets the form field names up correctly.  
As you’ve used params[:abc] in the controller, it’ll pick up the data  
fine.

For example:  
\<%= text\_field :story, :name %\>

will produce:

which will map to:

params[:story][:name]

When you put :abc in, it’s just another name for the fields.

The one thing you wont get is mapping of any data in @story mapped to  
the fields when you edit:

With:  
\<%= text\_field :story, :name %\>

Rails will try and find the instance variable @story and the attribute  
@story.name and put it in the value of the text field. If you  
put :abc, Rails will look for @abc and find nothing. It wont fail, but  
you wont see any of the story values in the form.

I guess this is just about getting your head round how forms are  
submitted and picked up server-side. I hope this has made it a bit  
clearer.

Steve

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<div class="post-metadata">

**Author:** ![chell](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/73ab20/32.png) [@chell](https://www.ruby-forum.com/u/chell)\
**Post date:** [April 26, 2007, 7:18pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029/5 "2007-04-26T19:18:13Z")

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Oh sorry,

the form’s actually:

\<% form\_for :abc do |f|%\>

name:   
 \<%= f.text\_field :name%\>

link:   
 \<%= f.text\_field :link%\>

\<%= submit\_tag%\>

\<% end %\>

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<div class="post-metadata">

**Author:** ![chell](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/73ab20/32.png) [@chell](https://www.ruby-forum.com/u/chell)\
**Post date:** [April 26, 2007, 8:39pm UTC](https://www.ruby-forum.com/t/question-regarding-form-for/93029/6 "2007-04-26T20:39:20Z")

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It might also be worth noting this form of the form\_for:

\<% form\_for :abc, @story do |f|%\>  
…  
…  
…

This should link the :abc params up to the @story instance variable,  
and should fix the issues with the update field mapping.