relations.md

Relation Management

One to One

Constraints

• Model1 explicitly belongs_to_one Model2 (via the model2 attribute)
• Model2 implicitly has_one Model1

Model1 Example

name: "foo"
model2: "bar"

Generated Model1 Model

class Model1

  def model2
    Model2.first(name: data['model2']
  end

end

Model2 Example

name: "bar"

Generated Model2 Model

class Model2

  def model1
    Model1.first(model2: data['name'])
  end

end

One to Many / Many to One

Constraints

• An episode explicitly belongs_to_one Show (via show attribute)
• A show implicitly has_many Episodes

Episode Example

name: "rtn-001"
title: "Podcasten im Futur II"
show: "rtn"

Generated Episode Model

class Episode

  def show
    # Reference by show name
    Show.first(name: 'rtn')
  end

end

Show Example

name: "rtn"
title: "Retinauten"
author: "Retinauten"

Generated Show Model

class Show

  def episodes
    Episode.find(show: 'rtn')
  end

end

Many to Many

Constraints

• An episode explicitly belongs_to_many hosts (via hosts array)
• A host implicitly has_many episodes

Episode Example

name: "rtc-s01e03"
title: "Würstchen und Sommer"
show: "rtc"
date: "1.8.2013"
hosts: [chef, marcel]

Generated Episode Model

class Episode

  def hosts
    data['hosts'].map do |host_name|
      Host.first(name: host_name)
    end
  end

end

Host Example

name: "chef"
full_name: "chef"
twitter_name: "grischder"

Generated Host Model

class Host

  def episodes
    Episode.find_match(host: data['name'])
  end

end