Question

I have a Picture class and I want to override returning the “description” database column value depending on some logic.

Is this valid in Rails? Can I always rely on the Class to call the class method before returning the database column value?

# database columns for Picture class
# description => String
# parent_id => Integer

class Picture < ActiveRecord::Base

  def description
    if parent_id.nil?
      self.description      
    else
      description = Picture.find(parent_id).description
    end
  end

end 

Couldn’t figure out where to find the answer in the Rails source code so any help would be appreciated.

Thanks!

EDIT

I’m trying to return a Picture’s description depending on whether or not it’s a child or parent Picture (they can be nested). The example is a bit contrived…I could easily avoid this by using a method without the same name as the database column…such as

def my_description
   if parent_id.nil? # return db data since no parent
      self.description
   else # return parent's description if one exists
      description = Picture.find(parent_id).description
   end
end

I guess I’m trying to be unnecessarily complicated here

Answer 1

It’s not totally clear what you’re trying to do, but you can use super to get the description value from within the method:

def description
  if parent_id.nil?
    super
  else
    self.description = Picture.find(parent_id).description
  end
end

Note that I changed the last line to use self.description = because I’m assuming you want to set the description value. If that’s not the case, then you don’t need to assign it to any variable.