ar_inheritance.rb

require "active_record"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")

ActiveRecord::Schema.define do
  create_table :languages do |t|
    t.string :type
  end
end

class Language < ActiveRecord::Base
  self.store_full_sti_class = false

  class Imperative < self
  end

  class Functional < self
  end
end

java = Language::Imperative.new
java.save!
puts java.attributes # {"id"=>1, "type"=>"Imperative"}

java = Language.new type: 'Language::Imperative'
java.save!
puts java.attributes # {"id"=>2, "type"=>"Language::Imperative"}

java = Language.new type: 'Imperative'
# Invalid single-table inheritance type: Imperative is not a subclass of Language (ActiveRecord::SubclassNotFound)