RoR - Convention Over Configuration

Variables

Category	Example
Local Variables	`variable_xyz`
Instance Variables	`@foo`
Class Variables	`@@foo`
Constant	`THIS_IS_A_CONSTANT`
Global Variables	`$global`

Models & Controllers & DB Tables

Category	Specification	Examples
Models	MixedCase; Singular	`class Post`
Controllers	MixedCase; Pluralization	`class PostsController`
Primary Key	Assumed to be named `id`	`id`
Foreign Key	Assumed to be named `XXX_id`	`author_id`
Join Tables	`XXX_YYY` with the table names in alphabetical order	`items_orders`

As for the normal tables, we usually use pluralization of the corresponding model name:

Model / Class	Table / Schema
`Article`	`articles`
`LineItem`	`line_items`
`Deer`	`deers`
`Mouse`	`mice`
`Person`	`people`

Migrations

When generating a migration in RoR, we can use the commands look like this:

rails generate migration CreatePosts title:string content:text

And db/migrate/YYYYMMDDHHMMSS_create_posts.rb file would be generated:

class CreatePosts < ActiveRecord::Migration[{Version-Number}]
  def change
    create_table :posts do |t|
      t.string :title
      t.text    :content
    end
  end
end

Because of the naming convention of RoR, if you name the migration Create${Models}, the table called ${Models} would be generated automatically, we have more of these conventions in RoR migration:

Convention	Meaning
AddXXXToYYY	A migration containing the appropriate `add_column` would be generated
RemoveXXXFromYYY	A migration containing the appropriate `remove_column` would be generated
CreateJoinTableXXXYYY	A migration containing `create_join_table` of XXX and YYY would be generated

October 9, 2017 · Ruby on Rails, Web