Rails4-子模型关联取决于父模型属性

Question

I have a User model that has an occupation attribute. Let's say a user can be a footballer or a tennisman When the user sign up, he selects the occupation, and can change it later.

My User model contains the most common attributes, like name, address, weight, contact infos. I want to store the other specific attributes in dedicated models, such as footballer_profile, tennissman_profiles

I can not use polymorphism since the infos are too different for a single model structure.

How can I declare to my User model a specific has_one condition depending on my "User.occupation" attribute ?

And is it the best way to go ? Thank you for your help

Answer 1

You can write :

class User < ActiveRecord::Base

  enum occupation: [ :footballer, :tennissman ]

  self.occupations.each do |type| 
    has_one type, -> { where occupation: type }, class_name: "#{type.classify}_profile"
  end
  #..
end

Please read #enum to understand how it works. Just remember , while you will be declaring, an attribute as enum , that attribute must be an integer column. If you don't want to go with enum , use a constant.

class User < ActiveRecord::Base

  Types = [ :footballer , :tennissman ]

  Types.each do |type| 
    has_one type, -> { where occupation: type.to_s }, class_name: "#{type.classify}_profile"
  end
  #..
end

Answer 2

Sounds like a case for polymorphism to me.

class User < ActiveRecord::Base
  belongs_to :occupational_profile, polymorphic: true
end

class FootballerProfile < ActiveRecord::Base
  has_one :user, as: :occupational_profile
end

This way you can simply build and associate the profile for the occupation they've chosen.