Module: Sequel::Plugins::LazyAttributes

Defined in:

lib/sequel/plugins/lazy_attributes.rb

Overview

The lazy_attributes plugin allows users to easily set that some attributes should not be loaded by default when loading model objects. If the attribute is needed after the instance has been retrieved, a database query is made to retreive the value of the attribute.

This plugin depends on the identity_map and tactical_eager_loading plugin, and allows you to eagerly load lazy attributes for all objects retrieved with the current object. So the following code should issue one query to get the albums and one query to get the reviews for all of those albums:

Album.plugin :lazy_attributes, :review
Sequel::Model.with_identity_map do
  Album.filter{id<100}.all do |a|
    a.review
  end
end

# You can specify multiple columns to lazily load:
Album.plugin :lazy_attributes, :review, :tracklist

Defined Under Namespace

Modules: ClassMethods, InstanceMethods

Class Method Summary

• .apply(model, *attrs) ⇒ Object

  Lazy attributes requires the identity map and tactical eager loading plugins.

• .configure(model, *attrs) ⇒ Object

  Set the attributes given as lazy attributes.

Class Method Details

.apply(model, *attrs) ⇒ Object

Lazy attributes requires the identity map and tactical eager loading plugins

# File 'lib/sequel/plugins/lazy_attributes.rb', line 24

def self.apply(model, *attrs)
  model.plugin :identity_map
  model.plugin :tactical_eager_loading  
end

.configure(model, *attrs) ⇒ Object

Set the attributes given as lazy attributes

# File 'lib/sequel/plugins/lazy_attributes.rb', line 30

def self.configure(model, *attrs)
  model.lazy_attributes(*attrs) unless attrs.empty?
end