数据迁移的还原

db/migrate/20160511055221_merge_two_homeworks.rb

@@ -6,8 +6,8 @@ class MergeTwoHomeworks < ActiveRecord::Migration
         work.update_column('homework_common_id', 3463)
       end
     end
-    #homework = HomeworkCommon.find 3387
-    #homework.destroy if homework
+    homework = HomeworkCommon.find 3387
+    homework.destroy if homework
     stu_works = StudentWork.where("homework_common_id = 3387")
     stu_work_ids = stu_works.empty? ? "(-1)" : "(" + stu_works.map{|work| work.id}.join(',') + ")"
     stu_work_tests = StudentWorkTest.where("student_work_id in #{stu_work_ids}")