Models

Create a Model

bin/rails g model Supplier name:string

bin/rails g model Product name:string:index sku:string{10}:uniq count:integer description:text supplier:references popularity:float 'price:decimal{10,2}' available:boolean availableSince:datetime image:binary

bin/rails g scaffold Product name:string:index sku:string{10}:uniq count:integer description:text supplier:references popularity:float 'price:decimal{10,2}' available:boolean availableSince:datetime image:binary

The Migration for creating a table

class CreateSuppliers < ActiveRecord::Migration[6.1]
  def change
    create_table :suppliers do |t|
      t.string :name

      t.timestamps
    end
  end
end

class CreateProducts < ActiveRecord::Migration[6.1]
  def change
    create_table :products do |t|
      t.string :name
      t.string :sku, limit: 10
      t.integer :count
      t.text :description
      t.references :supplier, null: false, foreign_key: true
      t.float :popularity
      t.decimal :price, precision: 10, scale: 2
      t.boolean :available
      t.datetime :availableSince
      t.binary :image

      t.timestamps
    end
    add_index :products, :name
    add_index :products, :sku, unique: true
  end
end

Destroy a Model

bundle exec rails db:rollback
rails destroy model Supplier

scopes
  where
  select
include
belongs_to
has_many
has_one
private
application record
before_validation
validates_presence_of
validates_uniqueness_of
before_validation
validate
enum
ActiveRecord::Base
require
after_update
module

include
freeze
select
map
where

Scopes

A scope is a query that you defined in your models that returns an active record relation, which allows you to chain queries together.

class Fruit < ApplicationRecord
  scope :with_juice, -> { where("juice > 0") }
end

Scope Implementation

Fruit.with_juice.with_round_shape.first(3)