diff --git a/app/controllers/admins/laboratory_subjects_controller.rb b/app/controllers/admins/laboratory_subjects_controller.rb
index d552b006e..c09697c7e 100644
--- a/app/controllers/admins/laboratory_subjects_controller.rb
+++ b/app/controllers/admins/laboratory_subjects_controller.rb
@@ -17,11 +17,15 @@ class Admins::LaboratorySubjectsController < Admins::BaseController
   def destroy
     return render_js_error('不能删除自建课程', type: :notify) if current_laboratory_subject.ownership?
 
-    current_subject = current_laboratory_subject.subject
-    current_subject.shixuns.destroy_all
-    current_subject.destroy!
-
-    render_delete_success
+    ActiveRecord::Base.transaction do
+      current_subject = current_laboratory_subject.subject
+      current_subject.shixuns.each do |shixun|
+        shixun.destroy!
+      end
+      current_subject.destroy!
+
+      render_delete_success
+    end
   end
 
 
diff --git a/app/models/shixun_tag_repertoire.rb b/app/models/shixun_tag_repertoire.rb
index 6cb311f7a..afd956350 100644
--- a/app/models/shixun_tag_repertoire.rb
+++ b/app/models/shixun_tag_repertoire.rb
@@ -3,5 +3,5 @@ class ShixunTagRepertoire < ApplicationRecord
   belongs_to :tag_repertoire
 
   has_many :memos, :through => :memo_tag_repertoires
-  has_many :memo_tag_repertoires, :dependent => :destroy
+  # has_many :memo_tag_repertoires, :dependent => :destroy
 end