班级作业加入题库，题库中该作业的引用数是零

app/controllers/homework_common_controller.rb

@@ -315,6 +315,14 @@ class HomeworkCommonController < ApplicationController
   #加入到题库
   def add_to_homework_bank
     if params[:type] && (params[:type].to_i == 1 || params[:type].to_i == 3)
+      if params[:type].to_i == 3
+        old_banks = HomeworkBank.where(:homework_common_id => @homework.id)
+        unless old_banks.blank?
+          old_banks.each do |bank|
+            bank.update_attributes(:quotes => (bank.quotes - 1) > 0 ? (bank.quotes - 1) : 0)
+          end
+        end
+      end
       homework_bank = add_to_homework_bank_f @homework
       homework_bank.save
       @homework.update_attributes(:homework_bank_id => homework_bank.id)

app/controllers/users_controller.rb

@@ -1499,6 +1499,7 @@ class UsersController < ApplicationController
           if params[:add_to_bank]
             homework_bank = add_to_homework_bank_f homework
             homework_bank.save
+            homework.update_attributes(:homework_bank_id => homework_bank.id)
           end
           redirect_to homework_common_index_path(:course => homework.course_id)
         end

app/helpers/application_helper.rb

@@ -4119,7 +4119,7 @@ end
 
 def add_to_homework_bank_f homework
   homework_bank = HomeworkBank.new(:name => homework.name, :description => homework.description, :user_id => homework.user_id, :homework_type => homework.homework_type,
-                                   :quotes => 0, :is_public => homework.course.is_public, :applicable_syllabus => homework.course.syllabus.title, :homework_common_id => homework.id)
+                                   :quotes => 1, :is_public => homework.course.is_public, :applicable_syllabus => homework.course.syllabus.title, :homework_common_id => homework.id)
   if homework.homework_type == 2 && homework.homework_detail_programing
     homework_bank.language = homework.homework_detail_programing.language
     homework.homework_tests.each_with_index do |homework_test|

app/models/homework_common.rb

@@ -36,6 +36,17 @@ class HomeworkCommon < ActiveRecord::Base
   after_update :update_activity
   after_save :act_as_course_activity
   after_destroy :delete_kindeditor_assets
+  before_destroy :update_homework_bank_quotes
+
+  #删除时更新题库中的引用数
+  def update_homework_bank_quotes
+    old_banks = HomeworkBank.where(:homework_common_id => self.id)
+    unless old_banks.blank?
+      old_banks.each do |bank|
+        bank.update_attributes(:quotes => (bank.quotes - 1) > 0 ? (bank.quotes - 1) : 0, :homework_common_id => nil)
+      end
+    end
+  end
 
   #作业类型
   def homework_type_ch

db/migrate/20170220065632_homework_bank_migration.rb

@@ -11,7 +11,7 @@ class HomeworkBankMigration < ActiveRecord::Migration
           course.homework_commons.each do |homework|
             unless homework.user.homework_banks.select("name").to_s.include?(homework.name)
               homework_bank = HomeworkBank.create(:user_id => homework.user_id, :name => homework.name, :description => homework.description, :homework_type => homework.homework_type,
-                                  :quotes => homework.quotes, :is_public => course.is_public, :applicable_syllabus => course.syllabus.title, :homework_common_id => homework.id, :created_at => homework.created_at)
+                                  :quotes => 1, :is_public => course.is_public, :applicable_syllabus => course.syllabus.title, :homework_common_id => homework.id, :created_at => homework.created_at)
               if homework.homework_type == 2 && homework.homework_detail_programing
                 homework_bank.update_attributes(:language => homework.homework_detail_programing.language, :standard_code => homework.homework_detail_programing.standard_code)
                 homework.homework_tests.each do |test|