update

db/migrate/20151018152439_create_programs_table.rb

@@ -0,0 +1,76 @@
+class CreateProgramsTable< ActiveRecord::Migration
+  class TempConference < ActiveRecord::Base
+    self.table_name = 'conferences'
+  end
+
+  class TempCfp < ActiveRecord::Base
+    self.table_name = 'cfps'
+  end
+
+  class TempCallForPaper < ActiveRecord::Base
+    self.table_name = 'call_for_papers'
+  end
+
+  class TempProgram < ActiveRecord::Base
+    self.table_name = 'programs'
+  end
+
+  def up
+    create_table :programs do |t|
+      t.references :conference
+      t.integer :rating, default: 0
+      t.boolean :schedule_public, default: false
+      t.boolean :schedule_fluid, default: false
+      t.timestamps
+    end
+
+    add_column :call_for_papers, :program_id, :integer
+
+    TempConference.all.each do |conference|
+      unless TempProgram.find_by(conference_id: conference.id)
+        program = TempProgram.new
+        program.conference_id = conference.id
+        program.save!
+
+        if (cfp = TempCallForPaper.find_by(conference_id: conference.id))
+          cfp.program_id = program.id
+          cfp.save!
+
+          program.rating = cfp.rating
+          program.schedule_public = cfp.schedule_public
+          program.schedule_fluid = cfp.schedule_changes
+          program.save!
+        end
+      end
+    end
+    remove_column :call_for_papers, :conference_id
+    remove_column :call_for_papers, :rating
+    remove_column :call_for_papers, :schedule_public
+    remove_column :call_for_papers, :schedule_changes
+    rename_table :call_for_papers, :cfps
+  end
+
+  def down
+    rename_table :cfps, :call_for_papers
+    add_column :call_for_papers, :conference_id, :integer
+    add_column :call_for_papers, :rating, :integer, default: 0
+    add_column :call_for_papers, :schedule_public, :boolean, default: false
+    add_column :call_for_papers, :schedule_changes, :boolean, default: false
+
+    TempConference.all.each do |conference|
+      if (program = TempProgram.find_by(conference_id: conference.id))
+        if (cfp = TempCallForPaper.find_by(program_id: program.id))
+          cfp.conference_id = program.conference_id
+          cfp.rating = program.rating
+          cfp.schedule_public = program.schedule_public
+          cfp.schedule_changes = program.schedule_fluid
+
+          cfp.save!
+        end
+      end
+    end
+
+    remove_column :call_for_papers, :program_id
+    drop_table :programs
+  end
+end