jhollinger / activerecord-viewmatic

Helpers for using database views in ActiveRecord

Viewmatic

Helpers for ActiveRecord apps that want to use database views easily. Both live and materialized views are supported. Easy to use:

1. Add activerecord-viewmatic to your Gemfile.
2. Define your views in db/views.rb or db/views/*.rb.
3. Use migrations to create or drop the defined views. (Your views will be automatically created when you run commands like rake db:setup and rake db:test:prepare.)
4. Define ActiveRecord models to access your views.

Define your views

db/views.rb

Viewmatic::Schema.define do
  view :reticulated_splines do |v|
    v.query "SELECT * FROM splines WHERE reticulated = 't'"
  end

  view :pending_orders do |v|
    v.query "SELECT * FROM orders WHERE status = 'Pending'"
    v.materialized true # only available in Postgres
  end
end

Create your migrations

class AddMyNewViews < ActiveRecord::Migration
  include Viewmatic::Migration

  def up
    create_view :reticulated_splines
    create_view :pending_orders
  end

  def down
    drop_view :reticulated_splines
    drop_view :pending_orders, materialized: true
  end
end

Create your models

app/models/views/reticulated_spline.rb

class Views::ReticulatedSpline < ActiveRecord::Base
  include Viewmatic::Model

  belongs_to :category
end

app/models/views/pending_order.rb

class Views::PendingOrder < ActiveRecord::Base
  include Viewmatic::Model

  has_many :line_items
end

You can access your view just like any other ActiveRecord model. Note that they are all read-only.

spline = Views::ReticulatedSpline.find(42)
spline.readonly?
=> true

Views::PendingOrder.where(created_on: Date.today).preload(:line_items).find_each do |order|
  # do stuff with each order
end

For materialized views, you can refresh the data simply by calling refresh! on the model:

PendingOrder.refresh!

Using ActiveRecord without Rails?

No problem! Everything will work fine - just add this line near the top of your Rakefile:

load 'tasks/viewmatic.rake'