battle.rb

battle.rb

class User
  has_one :character
end

class Character
  belongs_to :user
  has_many :battles
  has_many :battle_records
end

class Battle
  has_one :battle_record
end

class BattleRecords
  belongs_to :battle
  belongs_to :character, :foreign_key => :character_code
end

# 戦闘からキャラクターとる
# Battle.includes(:battle_record => :character).first.battle_record.character
#
# 戦績からキャラクターとる
# BattleRecord.includes(:character).first.character
#
# ユーザーから全部とる
# User.includes(:character => [:battles,:battle_records])