diff --git a/app/models/cdao/subject.rb b/app/models/cdao/subject.rb
index da263b7..86d5e14 100644
--- a/app/models/cdao/subject.rb
+++ b/app/models/cdao/subject.rb
@@ -49,6 +49,7 @@ class Cdao::Subject < Cdao::Base
   end
 
   searchable do
+    integer :id
     integer :parent_id
     integer :doctrine_ids, multiple: true
 
diff --git a/app/models/doctrine.rb b/app/models/doctrine.rb
index 4763f47..987cdea 100644
--- a/app/models/doctrine.rb
+++ b/app/models/doctrine.rb
@@ -46,6 +46,7 @@ class Doctrine < ApplicationRecord
   searchable do 
     text :content
 
+    integer :id
     integer :document_id
 
     integer :subject_ids, multiple: true