rails-models

Rails Models (ActiveRecord)

Quick Reference

Model Definition

class User < ApplicationRecord
  # Constants
  ROLES = %w[admin user guest].freeze
  
  # Associations
  has_many :posts, dependent: :destroy
  has_many :comments
  belongs_to :organization, optional: true
  
  # Validations
  validates :email, presence: true, uniqueness: true
  validates :name, presence: true, length: { minimum: 2 }
  validates :role, inclusion: { in: ROLES }
  
  # Callbacks
  before_save :normalize_email
  after_create :send_welcome_email
  
  # Scopes
  scope :active, -> { where(active: true) }
  scope :recent, -> { order(created_at: :desc) }
  
  # Class methods
  def self.search(query)
    where("name ILIKE ?", "%#{query}%")
  end
  
  # Instance methods
  def full_name
    "#{first_name} #{last_name}"
  end
  
  private
  
  def normalize_email
    self.email = email.downcase.strip
  end
end

Migrations

Creating Tables

class CreateUsers < ActiveRecord::Migration[7.0]
  def change
    create_table :users do |t|
      t.string :name, null: false
      t.string :email, null: false
      t.boolean :active, default: true
      t.integer :role, default: 0
      t.references :organization, foreign_key: true
      
      t.timestamps
    end
    
    add_index :users, :email, unique: true
  end
end

Modifying Tables

class AddFieldsToUsers < ActiveRecord::Migration[7.0]
  def change
    add_column :users, :bio, :text
    add_column :users, :avatar_url, :string
    add_reference :users, :manager, foreign_key: { to_table: :users }
    
    change_column_null :users, :email, false
    change_column_default :users, :active, from: nil, to: true
  end
end