# One Controller, Many models

**URL:** <https://www.ruby-forum.com/t/one-controller-many-models/57796>\
**Category:** Rails\
**Created:** [April 14, 2006, 7:05am UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796 "2006-04-14T07:05:19Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![pallan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/71c47a/32.png) [@pallan](https://www.ruby-forum.com/u/pallan)\
**Post date:** [April 14, 2006, 7:05am UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796/1 "2006-04-14T07:05:19Z")

</div>

Hello all,

I am working on a app right now that is going to replace a paper form  
process out client has. This process has quite a few forms (about 30)  
and different groups of forms (section) need to be filled out based on  
what information is required from the user. For example, here is a  
possible process of 2 users:

user 1 user 2  
Section 1 Section 1  
Section 2 Section 2  
Section 12 Section 3  
Section 13 Section 8  
Section 15 Section 15

I am trying to figure out the most efficient way to do this in Rails. I  
know I could just scaffold all the section tables, but then I would have  
30 controllers for 30 models that are doing pretty similar things. I  
believe that I will make the models for each section to allow for  
customization in terms of validation and such, but I feel there must be  
a way to avoid 30 controllers. Especially when each one will only  
differ by which model it is using.

What I would like to do is define the sections and their order for each  
“track”., then have a controller pull up the correct section model  
depending on where the user is in the process.

I am still getting the hang of Rails and application architecture/domain  
model stuff has always been a weakness. Any help or direction on how to  
handle this problem would be greatly appreciated. (any recommendations  
on some good places/books to learn software architecture would be nice  
to)

Thanks

Peer

---

<div class="post-metadata">

**Author:** ![pallan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/71c47a/32.png) [@pallan](https://www.ruby-forum.com/u/pallan)\
**Post date:** [April 14, 2006, 8:34am UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796/2 "2006-04-14T08:34:31Z")

</div>

Hi Peer,

I would take a look at single table inheritance  
([http://wiki.rubyonrails.org/rails/pages/SingleTableInheritance](http://wiki.rubyonrails.org/rails/pages/SingleTableInheritance)) to see  
if  
it helps solve your problem. Also, it’s pretty simple to load other  
models  
into your controller. If you want to load and use the model in  
“app/models/some\_model.rb” you’d use something like

def track  
require ‘some\_model’  
section\_1 = SomeModel.new()  
section\_1.save  
end

Validation would still reside in your models like normal.

Additionally, to avoid duplicating controller code across many  
controllers  
you can put it into app/controllers/application.rb .

I hope this helps!

Daniel

---

<div class="post-metadata">

**Author:** ![pallan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/71c47a/32.png) [@pallan](https://www.ruby-forum.com/u/pallan)\
**Post date:** [April 14, 2006, 2:24pm UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796/3 "2006-04-14T14:24:18Z")

</div>

Hi Daniel,

Unfortunately I don’t see how STI will help me in this case as each form  
(model) has very different information. If I were to put them in a  
single table it would have well over 100 columns. This is assuming that  
you are talking about STI for all the models. If not, could you please  
describe how I could use STI?

Peer

Daniel H. wrote:

> Hi Peer,
> 
> I would take a look at single table inheritance  
> ([http://wiki.rubyonrails.org/rails/pages/SingleTableInheritance](http://wiki.rubyonrails.org/rails/pages/SingleTableInheritance)) to see  
> if  
> it helps solve your problem. Also, it’s pretty simple to load other  
> models  
> into your controller. If you want to load and use the model in  
> “app/models/some\_model.rb” you’d use something like
> 
> def track  
> require ‘some\_model’  
> section\_1 = SomeModel.new()  
> section\_1.save  
> end
> 
> Validation would still reside in your models like normal.
> 
> Additionally, to avoid duplicating controller code across many  
> controllers  
> you can put it into app/controllers/application.rb .
> 
> I hope this helps!
> 
> Daniel

---

<div class="post-metadata">

**Author:** ![pallan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/71c47a/32.png) [@pallan](https://www.ruby-forum.com/u/pallan)\
**Post date:** [April 14, 2006, 4:38pm UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796/4 "2006-04-14T16:38:14Z")

</div>

Models don’t need to have their own controllers or full-blown scaffolds.  
Nothing is stopping you from having one user-accessible controller and  
one admin controller, for instance, and any controller can access any  
model.

And as long as you’re careful about security in the controller, there’s  
nothing wrong with having a single “edit” action in that one big  
controller that takes a Secton as an argument and presents an  
appropriate partial, for instance.

Peer A. wrote:

> Hello all,
> 
> I am working on a app right now that is going to replace a paper form  
> process out client has. This process has quite a few forms (about 30)  
> and different groups of forms (section) need to be filled out based on  
> what information is required from the user. For example, here is a  
> possible process of 2 users:
> 
> user 1 user 2  
> Section 1 Section 1  
> Section 2 Section 2  
> Section 12 Section 3  
> Section 13 Section 8  
> Section 15 Section 15
> 
> I am trying to figure out the most efficient way to do this in Rails. I  
> know I could just scaffold all the section tables, but then I would have  
> 30 controllers for 30 models that are doing pretty similar things. I  
> believe that I will make the models for each section to allow for  
> customization in terms of validation and such, but I feel there must be  
> a way to avoid 30 controllers. Especially when each one will only  
> differ by which model it is using.
> 
> What I would like to do is define the sections and their order for each  
> “track”., then have a controller pull up the correct section model  
> depending on where the user is in the process.
> 
> I am still getting the hang of Rails and application architecture/domain  
> model stuff has always been a weakness. Any help or direction on how to  
> handle this problem would be greatly appreciated. (any recommendations  
> on some good places/books to learn software architecture would be nice  
> to)
> 
> Thanks
> 
> Peer

---

<div class="post-metadata">

**Author:** ![pallan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/71c47a/32.png) [@pallan](https://www.ruby-forum.com/u/pallan)\
**Post date:** [April 14, 2006, 7:43pm UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796/5 "2006-04-14T19:43:59Z")

</div>

Thanks for everyone’s suggestions. I have a couple of ideas that I am  
going to experiment with. I have a feeling that this question is not  
that difficult to answer, but I am looking for a more complicated  
solution because it seems complicated.

Peer

Martin Bernd S. wrote:

> I’m not sure if I exactly understood what you want. So my suggestion is  
> short and maybe doesn’t fit your needs (also it’s definitly hackerish,  
> might be unsecure and there might be smarter ways to accomplish the same  
> task, forgive me, I’m relatively new to Ruby and RoR).
> 
> We needed an editor to internationalize several lookup tables (which had  
> some common fields, i.e. the different translations). Some of them had  
> parent relations. Instead of having a zillion views (and controllers) we  
> introduced two methods to each model parent\_class() and parent\_key()  
> returning the names to access the parent class / table (or nil in case  
> of a parent table).
> 
> Then we were passing the Model name (e.g. from a form) to the controller  
> and instanciated the corresponding objects with
> 
> def klazz  
> Object.instance\_eval(params[:model]).find(params[:id])  
> end
> 
> def parent\_klazz(object)  
> Object.instance\_eval(object.parent\_class)  
> end
> 
> This in addition with the parent\_key method should give you all options  
> to make such issue generic. Let me know if you need more info.
> 
> Note: This might contain errors, I didn’t compare this with the actual  
> code…

---

<div class="post-metadata">

**Author:** ![pallan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/71c47a/32.png) [@pallan](https://www.ruby-forum.com/u/pallan)\
**Post date:** [April 14, 2006, 4:56pm UTC](https://www.ruby-forum.com/t/one-controller-many-models/57796/6 "2006-04-14T16:56:00Z")

</div>

I’m not sure if I exactly understood what you want. So my suggestion is  
short and maybe doesn’t fit your needs (also it’s definitly hackerish,  
might be unsecure and there might be smarter ways to accomplish the same  
task, forgive me, I’m relatively new to Ruby and RoR).

We needed an editor to internationalize several lookup tables (which had  
some common fields, i.e. the different translations). Some of them had  
parent relations. Instead of having a zillion views (and controllers) we  
introduced two methods to each model parent\_class() and parent\_key()  
returning the names to access the parent class / table (or nil in case  
of a parent table).

Then we were passing the Model name (e.g. from a form) to the controller  
and instanciated the corresponding objects with

def klazz  
Object.instance\_eval(params[:model]).find(params[:id])  
end

def parent\_klazz(object)  
Object.instance\_eval(object.parent\_class)  
end

This in addition with the parent\_key method should give you all options  
to make such issue generic. Let me know if you need more info.

Note: This might contain errors, I didn’t compare this with the actual  
code…