Question

I’m trying to do a “ecommerce like” solution. When a product is defined, there are many option_values, e.g. whip cream => yes.

When I’m creating a line_item, my associations are like this.

class LineItem < ActiveRecord::Base
  belongs_to :cart
  belongs_to :order
  belongs_to :product
  belongs_to :shop
  ...

When a user chooses a product, he chooses options_values and a line_item must be created to store this.

Currently I’m not sure what is a good way to model the option_values in a line item.

My gut instinct is that a line_item has_many option_values, but it would seem weird to store foreign keys in option_values. The other thought is that line_item habtm option_values.

What would be a good way to model this line_item has_many option_values relationship, ideally storing the reference in the line_items table?

Answer 1

If your option_values are always boolean (whip cream => yes) you should have an OptionValues model with all available option_values and do habtm between LineItem and OptionValues.

If your option values are not always boolean (sugar => 2.spoons) then you must store this value (2.spoons) in the join model, so you should do something like this:

class LineItem < ActiveRecord::Base
   has_many :line_item_option_values
   ...
end

class  LineItemOptionValue < ActiveRecord::Base
   belongs_to :line_item
   belongs_to :option_value
end

class  OptionValue < ActiveRecord::Base
   has_many :line_item_option_values
end

And have the table for LineItemOptionValue a field for the value of the option.