Accessing one model from another

I have a model method that performs an algorithm, and there is another model that, after saving, in some cases, needs to refresh the algorithm result.

So, I would like to be able to do something like this:

class Model1 < ActiveRecord::Base
  after_save :update_score

  def up开发者_Go百科date_score
    if ...
      ...
    else
      # run_alg from class Model2
    end
  end
end

class Model2 < ActiveRecord::Base
  def run_alg
    ...
  end
end

Is this possible or do I have to move/copy run_alg into application.rb?

---

If it is a class method, you can just call Model2.run_alg, otherwise if it's an instance method you need to have an instance of Model2, which can be called like @model2_instance.run_alg (where @model2_instance is an instance variable of Model2).

Class Method:

class Model2 < ActiveRecord::Base
  def self.run_alg
    ...
  end

  # or

  class << self
     def run_alg
     ...
     end
  end
end

Instance method:

class Model2 < ActiveRecord::Base
  def run_alg
    ...
  end
end

To read more on class methods and instance methods, check this out.

---

Change method in your Model2 to instance_method by adding self.

class Model2 < ActiveRecord::Base
  def self.run_alg
    ...
  end
end

And call it from Model1 as Model2.run_alg