Rails when creating record, inserting belongs_to association

Question

i have a question about associations in rails. The situation is the following:

Models:

class Character < ActiveRecord::Base
  has_one :character_stats
end

class CharacterStats < ActiveRecord::Base
  belongs_to :character
end

Now i need to create stats when a new character is created.

What i doo is this at the moment, i feel like this is a workaround with rails. Is there a more "raily" way to do this?

  after_save :character_init  

  def character_init
    create_stats
  end

  def create_stats
    stats = CharacterStats.new
    stats.character_id = self.id // this bothers me!
    stats.save
  end

But i feel there should be something like this:

stats.character << self

Thank You in advance :)

EDIT:

here is how my model look in real life:

def create_stats
    race_stats = Race.find(race_id).race_stats
    class_stats = RaceClass.find(race_class_id).class_stats
    stats = CharacterStats.new
    stats.character_id = self.id
    stats.health = race_stats.health + class_stats.health
    stats.mana = race_stats.mana + class_stats.mana
    stats.intellect = race_stats.intellect + class_stats.intellect
    stats.armor = race_stats.armor + class_stats.armor
    stats.magic_resist = race_stats.magic_resist + class_stats.magic_resist
    stats.attack = race_stats.attack + class_stats.attack
    stats.defence = race_stats.defence + class_stats.defence
    stats.save
    self.character_stats_id = stats.id
  end

score 2 · Answer 1 · edited May 23 '17 at 12:29

first of all if you want to create CharacterStats after Character is created use after_create callback. About your question you can use ActiveRecord methods which looks like create_character_stats for creating model and build_character_stats for initializing model. So you can change your create_stats method to something like this

def create_stats
  self.create_character_stats
end

or you can change your after callback to this

after_create :create_character_stats

and then you don't need any method for this, but in this case you don't have ability to pass attributes to model creating.

also this question mentioned here Using build with a has_one association in rails

This is quite usefull to know, but i have to pass parameters... i will edit my post for that... — user2945241, Jul 01 '14 at 07:18

score 1 · Accepted Answer · answered Jul 01 '14 at 07:05

in rails way you can use the build_association method refer doc. Also the association should be created only when parent object is created so use after_create callback

class Character < ActiveRecord::Base
  has_one :character_stats

 after_create :create_stats

 def create_stats
    state = self.build_character_stats({}) # empty hash as you are not passing any attributes   
    state.save
 end

end

Also, the model name CharacterStats looks plural and that can violate the naming convention and can cause some issue like resolving association class on run time and so.

Rails when creating record, inserting belongs_to association

2 Answers2