# What am i doing? **URL:** \ **Category:** Rails\ **Created:** [September 6, 2008, 6:49pm UTC](https://www.ruby-forum.com/t/what-am-i-doing/147896 "2008-09-06T18:49:10Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![cherok](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/7cd45c/32.png) [@cherok](https://www.ruby-forum.com/u/cherok)\ **Post date:** [September 6, 2008, 6:49pm UTC](https://www.ruby-forum.com/t/what-am-i-doing/147896/1 "2008-09-06T18:49:10Z")
this is my first application in RoR and am kind of stuck. part of my confusion is where/when to use the model, controller or view. one of my tables is called gi\_maps which is basically a hash: sqlite\> select \* from gi\_maps; id|name 1|Gi 2|No-Gi another is called divisions which has gi\_maps hash and others: sqlite\> select \* from divisions; id|gi\_map\_id|rank\_map\_id|weight\_group\_map\_id|age\_group\_map\_id| created\_at|updated \_at 3|2|4|4|3|2008-09-05 21:28:32|2008-09-05 21:28:32 4|1|6|4|3|2008-09-05 21:29:01|2008-09-05 21:29:01 my default show “view” (divisions/show.html.erb) just displays the id’s for each entry: Gi or No-Gi Rank Weight group Age group 2 4 4 3 Show Edit Destroy 1 6 4 3 Show Edit Destroy divisions/show.html.erb: . . **Gi or No-Gi:** \<%=h @division.gi\_map\_id %\> . . . so all of this works fine… except for the fact that people like to see words instead of numbers 🙂 so what i’ve tried to do is use my model (models/division.rb) to “collect” the corresponding “name” value for a given hash id (ie. gi\_map\_id). but for some reason this isn’t working and i can’t think of any other way to do it except for placing it in the controller or view section. but i _think_ this should be done at the model level. here are the files and errors the way i’m doing it (i’ll truncate the files for readability): models/gi\_map.rb: class GiMap \< ActiveRecord::Base belongs\_to :divison end models/division.rb: class Division \< ActiveRecord::Base belongs\_to :match def self.gi\_map\_name GiMap.first(:conditions =\> [“id = ?”, self.id]).name end end controllers/divisions\_controller.rb: . . def show @division = Division.find(params[:id]) ``` respond_to do |format| format.html # show.html.erb format.xml { render :xml => @division } end ``` end . . views/divisons/show.html.rb: . . **Gi or No-Gi:** \<%=h @division.gi\_map\_name %\> . . . and here is the error when trying to “show” one record: NoMethodError in Divisions#show Showing divisions/show.html.erb where line #3 raised: undefined method `gi\_map\_name’ for #Division:0x478b9b0 Extracted source (around line #3): 1: 2: **Gi or No-Gi:** 3: \<%=h @division.gi\_map\_name %\> 4: 5: 6: i hope this isn’t a total noob question! but i’ve already written this application in php/mysql and am just rewriting in an effort to learn RoR. so any help or tips would be greatly appreciated. thanks! ron ---
**Author:** ![cherok](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/7cd45c/32.png) [@cherok](https://www.ruby-forum.com/u/cherok)\ **Post date:** [September 6, 2008, 6:51pm UTC](https://www.ruby-forum.com/t/what-am-i-doing/147896/2 "2008-09-06T18:51:31Z")
Defining methods with the self prefix denotes a class method. You are calling the method on an instance object. Remove the self and you will be good to go. ---
**Author:** ![cherok](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/7cd45c/32.png) [@cherok](https://www.ruby-forum.com/u/cherok)\ **Post date:** [September 6, 2008, 7:19pm UTC](https://www.ruby-forum.com/t/what-am-i-doing/147896/3 "2008-09-06T19:19:03Z")
wow! i was pretty far off 🙂 thanks for the tips! i would like to know more about when/where and what the implications are for using the has\_one, belongs\_to, etc. keywords. any links that would help me better understand what the hell i’m doing ? 🙂 btw… i DO get what you are saying… after changing the belongs\_to and has\_one… i can just do this in my view: **Gi or No-Gi:** \<%=h @division.gi\_map.name %\> thanks again! On Sep 6, 12:53 pm, Frederick C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![cherok](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/7cd45c/32.png) [@cherok](https://www.ruby-forum.com/u/cherok)\ **Post date:** [September 6, 2008, 6:54pm UTC](https://www.ruby-forum.com/t/what-am-i-doing/147896/4 "2008-09-06T18:54:27Z")
On Sep 6, 5:36 pm, Ron DeMeritt [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > this is my first application in RoR and am kind of stuck. part of my > confusion is where/when to use the model, controller or view. class Division \< ActiveRecord::Base > belongs\_to :match > > def self.gi\_map\_name > GiMap.first(:conditions =\> [“id = ?”, self.id]).name > end > end You’ve created a class method (that’s what def self. does) whereas this should really be an instance method. Usually you’d handle this via some associations. GiMap should have has\_one :division (and not belongs\_to :division - that would indicate that the gi\_maps table has a division\_id column) and division should belongs\_to :gi\_map (and it does as required have a gi\_map\_id column). Then you’d just write (I suspect that personally I wouldn’t bother) def gi\_map\_name gi\_map.name end Fred ---
**Author:** ![cherok](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/7cd45c/32.png) [@cherok](https://www.ruby-forum.com/u/cherok)\ **Post date:** [September 7, 2008, 5:10pm UTC](https://www.ruby-forum.com/t/what-am-i-doing/147896/5 "2008-09-07T17:10:04Z")
> **[\#3 Find Through Association - RailsCasts](http://railscasts.com/episodes/3-find-through-association)** > > Short Ruby on Rails screencasts containing tips, tricks and tutorials. Great for both novice and experienced web developers.