Advie for model relationships

rubyonrails-talk
1

I have 3 models, let's call them Recipe, Fruit and Nut, and I need a DRY way to set up their relationships.

Fruits and Nuts have different sets of properties Fruits and Nuts go into a Recipe A join model would be useful to track how much Fruit or Nut goes into a Recipe Different Recipes may use a Nut with the name, but different property values I might want to add a Twig or Llama model to my Recipes

Right now I have a separate join models that do pretty much the same for each of Fruit and Nut, but it's getting really wet (opposite of DRY). It works just fine, but the code is getting really redundant.

Untill I can hack rails so has_many :through works with polymorphic associations, what is a good way to do this?

class Recipe < AR::B   has_many :fruitadditions   has_many :fruits, :through => :fruitaddition

  has_many :nutadditions   has_many :nuts, :through => :nutaddition end

class Fruit < AR::B   has_many :fruitadditions   has_many :recipes, :through => :fruitadditions end

class Nut < AR::B   has_many :nutadditions   has_many :recipes, :through => :nutadditions end

TIA

--Dean

2

So I thought I would share the solution I came up with.

class Recipe < AR::B   has_many :fruitadditions, :conditions => [ 'fruit_id IS NOT NULL' ]   has_many :fruits, :through => :fruitaddition

  has_many :nutadditions, :conditions => [ 'nut_id IS NOT NULL' ]   has_many :nuts, :through => :nutaddition end

class Ingredient < ActiveRecord::Base   belongs_to :recipe

  def some_methods     # ....   end end

class Fruitingredient < Ingredient   belongs_to :fruit end

class Fruit < ActiveRecord::Base   has_many :fruitingredients   has_many :recipes, :through => :fruitingredients end

class Twigingredient < Ingredient   belongs_to :twig end

class Twig < ActiveRecord::Base   has_many :twigingredients   has_many :recipes, :through => :twigingredients end

So I have a single ingredients table with the FKs for each separate ingredient table. It seems just a little hack-ey, but works well.

--Dean