Rails get data while using single table inheritance -

i have company, indstry type, major category , minor category in app. used single table inheritance major , minor categories. have following association.

class industrytype < activerecord::base has_many :companies has_many :categories end  class company < activerecord::base   belongs_to :industry_type end   class category < activerecord::base   belongs_to :industry_type    def self.types     %w(major minor)   end     scope :majors, -> { where(type: 'major') }    scope :minors, -> { where(type: 'minor') }   end  class major < category; end  class minor < category; end   industrytype.first.categories -> returns both major , minor category of industry type industrytype.first.categories.majors -> returns major category of industry type industrytype.first.categories.minors -> returns minor category of industry type major.all -> returns major categories minor.all -> returns minor categories 

how specific company major or minor category?

company.last.industry_type.categories.majors -> returns industry based major categories 

i'll way:

class industrytype < activerecord::base   has_many :companies   has_many :mayors   has_many :minors   # keep if need relation both categories   has_many :categories end  class company < activerecord::base   belongs_to :industry_type end   class category < activerecord::base   belongs_to :industry_type    def self.types     %w(major minor)   end  end  class major < category; end  class minor < category; end   industrytype.first.categories -> returns both major , minor category of industry type industrytype.first.majors -> returns major category of industry type industrytype.first.minors -> returns minor category of industry type major.all -> returns major categories minor.all -> returns minor categories 

i remove scopes on category, , associate industrytype both types of category (minor & mayor).

how specific company major or minor category?

company.last.industry_type.majors -> returns major categories of company based on industry type. company.last.industry_type.minors -> returns minor categories of company based on industry type.