清理课程状态表，修正同一课程出现多次的BUG

app/models/course_status.rb

@@ -1,3 +1,7 @@
 class CourseStatus < ActiveRecord::Base
   attr_accessible :changesets_count, :course_ac_para, :course_id, :grade, :watchers_count
+
+  belongs_to :course
+  validates_presence_of :course_id
+  validates_uniqueness_of :course_id
 end

db/migrate/20140603042015_stored_course_procedure.rb

@@ -31,7 +31,7 @@ class StoredCourseProcedure < ActiveRecord::Migration
             courseStatus.watchers_count = projectstatus.watchers_count
             courseStatus.grade = projectstatus.grade
             courseStatus.course_ac_para = projectstatus.course_ac_para
-            courseStatus.save(:validate => false)
+            courseStatus.save()
           end
         end
       end

db/migrate/20140704034832_clear_course_status.rb

@@ -0,0 +1,16 @@
+class ClearCourseStatus < ActiveRecord::Migration
+  def up
+    # 删除重复的课程状态
+    # 之前做迁移的时候未加验证可能引起此问题
+    courseidlist = "(-1"
+    CourseStatus.all.each do |status|
+      sql = "delete from course_statuses where course_id=" + status.course_id.to_s  + " and id<>" + status.id.to_s +
+      " and course_id not in " +courseidlist + ")"
+      courseidlist += "," +  status.course_id.to_s;
+      execute(sql)
+    end
+  end
+
+  def down
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20140703085204) do
+ActiveRecord::Schema.define(:version => 20140704034832) do
 
   create_table "activities", :force => true do |t|
     t.integer "act_id",   :null => false
@@ -794,10 +794,10 @@ ActiveRecord::Schema.define(:version => 20140703085204) do
   end
 
   create_table "relative_memos", :force => true do |t|
-    t.integer  "osp_id",                                :null => false
+    t.integer  "osp_id"
     t.integer  "parent_id"
     t.string   "subject",                                                   :null => false
-    t.text     "content",                               :null => false
+    t.text     "content",            :limit => 16777215,                    :null => false
     t.integer  "author_id"
     t.integer  "replies_count",                          :default => 0
     t.integer  "last_reply_id"