Rails 3.2：（activerecord）我该如何建模？

Question

I have three models: RequestForQuote , CounterQuote < RequestForQuote [inherit RequestForQuote] and Proposition .

A request_for_quote has_many propositions , and a proposition can act as a tree with a counter_quote .

I already have :

class RequestForQuote < ActiveRecord::Base
  has_many :propositions, :dependent => :destroy
end

class CounterQuote < RequestForQuote

end

class Proposition < ActiveRecord::Base
  belongs_to :request_for_quote
end

How can I model it ? Thanks.

Answer 1

If a Proposition can have only one CounterQuote, you can use this:

class RequestForQuote < ActiveRecord::Base
  has_many :propositions, :dependent => :destroy
end

class CounterQuote < RequestForQuote
  belongs_to :proposition
end

class Proposition < ActiveRecord::Base
  belongs_to :request_for_quote
  has_one :counter_quote
end

CounterQuote would have attributes proposition and propositions , which is not very clear, consider renaming of these.

If CounterQuote can have many propositions, I agree with Tass, you can merge CounterQuote and RequestForQuote. If you need a tree structure (with parent and children), look at existing gems like awesome_nested_set .