ENH: Added an active attribute to Questions.

This allows us to enable/disable questions in a question paper.  Only
questions that are active are used to create a question paper. I've also
modified the load_exam/load_questions_xml to deactivate rather than
delete old questions.

4 files changed, 16 insertions, 8 deletions

diff --git a/exam/management/commands/load_exam.py b/exam/management/commands/load_exam.py
index 157a94a..3f247a1 100644
--- a/exam/management/commands/load_exam.py
+++ b/exam/management/commands/load_exam.py
@@ -8,9 +8,10 @@ from django.core.management.base import BaseCommand
 from exam.models import Question, Quiz
 
 def clear_exam():
-    """Delete all questions from the database."""
+    """Deactivate all questions from the database."""
     for question in Question.objects.all():
-        question.delete()
+        question.active = False
+        question.save()
         
     # Deactivate old quizzes.
     for quiz in Quiz.objects.all():
diff --git a/exam/management/commands/load_questions_xml.py b/exam/management/commands/load_questions_xml.py
index 1e9cfde..aa403dd 100644
--- a/exam/management/commands/load_questions_xml.py
+++ b/exam/management/commands/load_questions_xml.py
@@ -18,9 +18,10 @@ def decode_html(html_str):
             lambda m: unichr(name2codepoint[m.group(1)]), html_str)
 
 def clear_questions():
-    """Delete all questions from the database."""
+    """Deactivate all questions from the database."""
     for question in Question.objects.all():
-        question.delete()
+        question.active = False
+        question.save()
 
 def load_questions_xml(filename):
     """Load questions from the given XML file."""
diff --git a/exam/models.py b/exam/models.py
index 09529b9..fb06576 100644
--- a/exam/models.py
+++ b/exam/models.py
@@ -15,9 +15,11 @@ class Profile(models.Model):
 ################################################################################
 class Question(models.Model):
     """A question in the database."""
-    # An optional one-line summary of the question.
+
+    # A one-line summary of the question.
     summary = models.CharField(max_length=256)
-    # The question text.
+
+    # The question text, should be valid HTML.
     description = models.TextField()
     
     # Number of points for the question.
@@ -26,7 +28,11 @@ class Question(models.Model):
     # Test cases for the question in the form of code that is run.
     # This is simple Python code.
     test = models.TextField()
-    
+
+    # Is this question active or not.  If it is inactive it will not be used
+    # when creating a QuestionPaper.
+    active = models.BooleanField(default=True)
+
     def __unicode__(self):
         return self.summary
 
diff --git a/exam/views.py b/exam/views.py
index 729b1e6..b880c4d 100644
--- a/exam/views.py
+++ b/exam/views.py
@@ -133,7 +133,7 @@ def start(request):
                     | stat.S_IRUSR | stat.S_IWUSR | stat.S_IXUSR \
                     | stat.S_IRGRP | stat.S_IWGRP | stat.S_IXGRP)
 
-        questions = [ str(_.id) for _ in Question.objects.all() ]
+        questions = [ str(_.id) for _ in Question.objects.filter(active=True) ]
         random.shuffle(questions)
         
         new_paper.questions = "|".join(questions)