Question

i have a model say modela with a calculate field. like below

class modelA < ActiveRecord::Base
      attr_accessor : calc_field

def calc_field
   @stuff =  modelb.all
   //do fancy things with stuff
end

end 

now my problem is if i have 100 records of modelA. the modelb.all gets called a 100times. but its the same dataset each time. but the query gets sent out a 100 times.

is there anyway/anywhere i can declare @stuff globally so its gets shared across all instances of modelA. so it gets called only once.

Answer 1

There are numerous ways on how to tackle this problem.

Solution A:

class modelA < ActiveRecord::Base
  attr_accessor : calc_field

  def calc_field(modelb_info)
     @stuff =  modelb_info
     //do fancy things with stuff
  end

end

And then in your code work flow

model_info = ModelB.all
model_a_array.collect{|model_a| model_a model_info}

Solution B

class modelA < ActiveRecord::Base
  @@stuff ||= ModelB.all
end