从另一个模型访问一个模型 [英] Accessing one model from another

问题描述

我有一个执行算法的模型方法，还有另一种模型，在某些情况下，保存后需要刷新算法结果.

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.

因此，我希望能够执行以下操作:

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

class Model1 < ActiveRecord::Base
  after_save :update_score

  def update_score
    if ...
      ...
    else
      # run_alg from class Model2
    end
  end
end

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

这可能吗?还是我必须将run_alg移动/复制到application.rb中?

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

推荐答案

如果是类方法，则可以调用Model2.run_alg；否则，如果您是实例方法，则需要具有Model2的实例.称为@model2_instance.run_alg(其中@ model2_instance是Model2的实例变量).

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方法:

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

  # or

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

实例方法:

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

要详细了解类方法和实例方法，请检查一下.

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

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