diff --git a/app/models/questionnaire.rb b/app/models/questionnaire.rb
index d576bc421..e11b081ed 100644
--- a/app/models/questionnaire.rb
+++ b/app/models/questionnaire.rb
@@ -2,20 +2,36 @@ class Questionnaire < ApplicationRecord
   belongs_to :assignment, foreign_key: 'assignment_id', inverse_of: false
   belongs_to :instructor
   has_many :questions, dependent: :destroy # the collection of questions associated with this Questionnaire
-  before_destroy :check_for_question_associations
+  before_destroy :prevent_destroy_if_questions_exist
+  has_many :assignment_questionnaires, dependent: :destroy
+  has_many :assignments, through: :assignment_questionnaires
 
   validate :validate_questionnaire
   validates :name, presence: true
   validates :max_question_score, :min_question_score, numericality: true 
 
+  # Does this questionnaire contain true/false questions?
+  def true_false_questions?
+    questions.where(type: 'Checkbox').exists?
+  end
+
+  def delete
+    assignments.each do |assignment|
+      raise "The assignment #{assignment.name} uses this questionnaire.
+            Do you want to <A href='../assignment/delete/#{assignment.id}'>delete</A> the assignment?"
+    end
+    questions.each(&:delete)
+    destroy
+  end
+  
   # clones the contents of a questionnaire, including the questions and associated advice
-  def self.copy_questionnaire_details(params)
+  def self.copy(params)
     orig_questionnaire = Questionnaire.find(params[:id])
     questions = Question.where(questionnaire_id: params[:id])
     questionnaire = orig_questionnaire.dup
     questionnaire.name = 'Copy of ' + orig_questionnaire.name
-    questionnaire.created_at = Time.zone.now
-    questionnaire.updated_at = Time.zone.now
+    questionnaire.created_at = Time.now
+    questionnaire.updated_at = Time.now
     questionnaire.save!
     questions.each do |question|
       new_question = question.dup
@@ -34,8 +50,8 @@ def validate_questionnaire
     errors.add(:name, 'Questionnaire names must be unique.') if results.present?
   end
 
-  # Check_for_question_associations checks if questionnaire has associated questions or not
-  def check_for_question_associations
+  # Checks if questionnaire has associated questions or not
+  def prevent_destroy_if_questions_exist
     if questions.any?
       raise ActiveRecord::DeleteRestrictionError.new(:base, "Cannot delete record because dependent questions exist")
     end