Ror Naming

Naming in Ruby on Rails - a Quick Reference ! Introduction. In Rails it is so important to get the naming conventions correct. This is all part of the DRY ( Don't Repeat Yourself ) paradigm of Rails. This is particularly important at the beginning of a new project. Grasping this logic will go a long way to gaining a full understanding of Rails . If you get it wrong, progress can be frustrating. This document describes the naming conventions Ruby on Rails uses in regard to the models, controllers, source files, classes, table names, relationships, methods, routing & the corresponding folder structures. These are created via the 'ruby script/' command line generator. I will use a simple Contact / Category two table structure in a 'play' project. On page three there are images showing the folder structure in the app folder and the table names in SQLite Manager. To emphasise the singular or plural names they are highlighted in bold. This is aimed at beginners & I hope folk find it useful. Project Creation: The name of a new Rails project is entirely up to you. But keep it simple, best not to have any special characters. ( e.g. 'rails play' ). Model, Controller & Scaffold Generators. Models. A model created via the command line generator, refers to the model as singular. So in our example of categories and contacts we use.... $ ruby script/generate model Category name:string $ ruby script/generate model Contact firstname:string surname:string category_id:integer

When the migration files for these models are created with 'rake db:migrate', the tables created will be plural ( i.e. categories and contacts ). The model files that are created are singular within the apps/models folder e.g. category.rb ( see image below ) Class names within those model files are singular: e.g. class Contact < ActiveRecord::Base end

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Controllers. When a controller is created via 'ruby script/generate' the plural name is used ( unlike models ). i.e. $ ruby script/generate controller Contacts index The created controller file is plural in nature. ( i.e. contacts_controller.rb ) The corresponding view files are created within a folder (auto-created if it does not already exist) that is plural. ( e.g. app/views/contacts/index.html.erb ) Controller Class names are plural in nature. i.e. class ContactsController < ApplicationController def index ... Scaffold - If scaffold is used as the generator (which creates the model and controller in one action!) the information described above is identical. Routing. When the Scaffold generator is used it also creates entries in your routes.rb file ( located in the config folder ) Restful entries generated are of a plural nature and look like this: map.resources :contacts map.resources :categories Relationships. In the model files the relationship code uses singular references for belongs to. e.g. class Contact < ActiveRecord::Base belongs_to :category end and plural references for has_many e.g. class Category < ActiveRecord::Base has_many :contacts end

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Controller Methods. In controllers, find methods use the singular name of the model. e.g. def index @categories = Category.find(:all) Note that the instance variable @categories can be any name, but using the plural name here is logical as the index method is finding all the categories. e.g. 2 def show @category = Category.find(params[:id]) Note that the instance variable @category can be any name, but using the singular name here is logical as the show method is finding a single category.

Figure – 2 Shows the plural table names created in our 'play' project.

Figure – 1 Shows the names of files and folders within our 'play' project app folder. original ver: last update:

July 7th 2008 August 11th 2008

Comments & Feedback to: Dave Porter @ dj software <email> dave at dj-software dot com dot au

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