diff --git a/app/controllers/homework_common_controller.rb b/app/controllers/homework_common_controller.rb
index 8ca31926..a7a7d8c0 100644
--- a/app/controllers/homework_common_controller.rb
+++ b/app/controllers/homework_common_controller.rb
@@ -671,6 +671,7 @@ class HomeworkCommonController < ApplicationController
 
   def destroy
     if @homework.destroy
+      StudentWork.where(:homework_common_id => @homework.id).destroy_all
       #更新CourseHomeworkStatistics中每个学生的未交作品数、已交作品数、迟交作品数
       # hw_count = @course.homework_commons.includes(:homework_detail_manual).where("homework_detail_manuals.comment_status > 0").count
       # homework_ids = @course.homework_commons.empty? ? "(-1)" : "(" + @course.homework_commons.map{|hw| hw.id}.join(",") + ")"
@@ -1347,7 +1348,7 @@ class HomeworkCommonController < ApplicationController
   def find_homework
     @homework = HomeworkCommon.find params[:id]
     @homework_detail_manual = @homework.homework_detail_manual
-    @homework_detail_programing = @homework.homework_detail_programing
+    # @homework_detail_programing = @homework.homework_detail_programing
     @homework_detail_group = @homework.homework_detail_group
     @course = @homework.course
   rescue
diff --git a/app/models/homework_common.rb b/app/models/homework_common.rb
index 6bcdb8fd..7d75daa2 100644
--- a/app/models/homework_common.rb
+++ b/app/models/homework_common.rb
@@ -15,7 +15,7 @@ class HomeworkCommon < ActiveRecord::Base
   belongs_to :homework_bank
   has_many :homework_group_settings, :dependent => :destroy
   has_one :homework_detail_manual, :dependent => :destroy
-  has_one :homework_detail_programing, :dependent => :destroy
+  # has_one :homework_detail_programing, :dependent => :destroy
   has_one :homework_detail_group, :dependent => :destroy
   has_one :homework_commons_shixuns, :dependent => :destroy
   has_many :homework_challenge_settings, :dependent => :destroy
@@ -24,21 +24,21 @@ class HomeworkCommon < ActiveRecord::Base
   has_many :homework_review_results, :dependent => :destroy   # 学生的查重情况
 
   belongs_to :course_homework_category
-  has_many :student_work_projects, :dependent => :destroy
-  has_many :homework_tests, :dependent => :destroy
-  has_many :homework_samples, :dependent => :destroy
-  has_many :student_works, :dependent => :destroy, :conditions => "student_works.is_test=0 and student_works.is_delete != 1"
+  has_many :student_work_projects
+  # has_many :homework_tests, :dependent => :destroy
+  # has_many :homework_samples, :dependent => :destroy
+  has_many :student_works, :conditions => "student_works.is_test=0 and student_works.is_delete != 1"
   has_many :student_works_evaluation_distributions, :through => :student_works #一个作业的分配的匿评列表
   has_many :journals_for_messages, :as => :jour, :dependent => :destroy
-  has_many :apply_homeworks, :dependent => :destroy
+  has_many :apply_homeworks
   has_many :praise_tread, as: :praise_tread_object, dependent: :destroy
   has_one :praise_tread_cache, as: :object, dependent: :destroy
-  has_many :acts, :class_name => 'Activity', :as => :act, :dependent => :destroy #用户活动
+  # has_many :acts, :class_name => 'Activity', :as => :act, :dependent => :destroy #用户活动
   has_and_belongs_to_many :shixuns
   # 课程动态
   has_many :course_acts, :class_name => 'CourseActivity',:as =>:course_act ,:dependent => :destroy
   # 课程消息
-  has_many :course_messages, :class_name =>'CourseMessage', :as => :course_message, :dependent => :destroy
+  # has_many :course_messages, :class_name =>'CourseMessage', :as => :course_message, :dependent => :destroy
   has_many :tidings, as: :container, dependent: :destroy
   acts_as_attachable
   acts_as_event :title => Proc.new {|o| "#{l(:label_course_homework)} ##{o.id}: #{o.name}" },
@@ -48,7 +48,7 @@ class HomeworkCommon < ActiveRecord::Base
   # after_create :act_as_activity
   after_update :update_activity
   after_save :act_as_course_activity
-  after_destroy :delete_kindeditor_assets
+  # after_destroy :delete_kindeditor_assets
   before_destroy :update_homework_bank_quotes
 
   #删除时更新题库中的引用数
diff --git a/app/models/student_work.rb b/app/models/student_work.rb
index b6b64523..573b2cbe 100644
--- a/app/models/student_work.rb
+++ b/app/models/student_work.rb
@@ -13,9 +13,9 @@ class StudentWork < ActiveRecord::Base
   has_many :student_works_scores, :dependent => :destroy
   has_many :challenge_work_scores, :dependent => :destroy
   belongs_to :project
-  has_many :student_work_tests, order: 'id desc'
+  # has_many :student_work_tests, order: 'id desc'
   # course's message
-  has_many :course_messages, :class_name =>'CourseMessage', :as => :course_message, :dependent => :destroy
+  # has_many :course_messages, :class_name =>'CourseMessage', :as => :course_message, :dependent => :destroy
   has_many :attachments, :dependent => :destroy
   has_many :tidings, as: :container, dependent: :destroy
   belongs_to :myshixun
diff --git a/db/migrate/20190314010614_add_index_to_homework.rb b/db/migrate/20190314010614_add_index_to_homework.rb
new file mode 100644
index 00000000..a6db7a29
--- /dev/null
+++ b/db/migrate/20190314010614_add_index_to_homework.rb
@@ -0,0 +1,8 @@
+class AddIndexToHomework < ActiveRecord::Migration
+  def change
+    add_index :homework_detail_manuals, :homework_common_id
+    add_index :homework_commons_shixuns, :homework_common_id
+    add_index :student_works_evaluation_distributions, :student_work_id
+    add_index :tidings, :container_id
+  end
+end