ruby on rails - ActiveRecord Eager Load model that isn't belongs_to -

i'm running issue n+1 queries , want eager load relationship, except i'm having trouble defining relationship. it's complicated, haha, hear me out.

i have 2 models.

class pokemon < activerecord::base   belongs_to :pokemon_detail, primary_key: "level", foreign_key: "level" end  class pokemondetail < activerecord::base   has_one :pokemons, primary_ley: "level", foreign_key: "level" end 

let's say, have following record:

<pokemon id: 1, name: "squirtle", level: 1> 

which correspond following pokemondetail

<pokemondetail id: 1, name: "squirtle", level: 1, health: 150> 

and can eager loaded pokemon.all.includes(:pokemon_detail), however, want eager load information 1 level higher.

<pokemondetail id: 2, name: "squirtle", level: 2, health: 300> 

i find information 1 level higher following method within pokemon model.

def next_level_info   pokemondetail.where(level: self.level + 1) end 

but isn't eager loaded. ideas?

1. refactor schema first, make more sense:

   pokemons { current_level_value, name } pokemon_levels {value, pokemon_id (foreign key), health } 

2. redefine models this:

   class pokemonlevel < activerecord::base   belongs_to :pokemon end   class pokemon < activerecord::base   has_many :pokemon_levels   has_one :current_pokemon_level, -> { joins(:pokemon).where('pokemons.current_level_value = pokemon_levels.value') },        foreign_key: :pokemon_id, class_name: 'pokemonlevel'   has_one :next_pokemon_level, -> { joins(:pokemon).where('pokemons.current_level_value + 1 = pokemon_levels.value') },        foreign_key: :pokemon_id, class_name: 'pokemonlevel' end 

3. simply use eg:

   pokemon.includes(:current_pokemon_level, :next_pokemon_level).find(123) 

i use pokemonlevel instead of pokemondetail, because clearer me