Hotfix for OC-639: Database conflict between mentoring and problem_builder

problem_builder/models.py

@@ -29,10 +29,11 @@ class Answer(models.Model):
     """
     Django model used to store AnswerBlock data that need to be shared
     and queried accross XBlock instances (workaround).
+
+    TODO: Deprecate this and move to edx-submissions
     """
 
     class Meta:
-        db_table = 'mentoring_answer'
         unique_together = (('student_id', 'course_id', 'name'),)
 
     name = models.CharField(max_length=50, db_index=True)

problem_builder/south_migrations/0001_initial.py

@@ -0,0 +1,44 @@
+# -*- coding: utf-8 -*-
+from south.db import db
+from south.v2 import SchemaMigration
+
+
+class Migration(SchemaMigration):
+
+    def forwards(self, orm):
+        # Adding model 'Answer'
+        db.create_table('problem_builder_answer', (
+            ('id', self.gf('django.db.models.fields.AutoField')(primary_key=True)),
+            ('name', self.gf('django.db.models.fields.CharField')(max_length=50, db_index=True)),
+            ('student_id', self.gf('django.db.models.fields.CharField')(max_length=32, db_index=True)),
+            ('course_id', self.gf('django.db.models.fields.CharField')(max_length=50, db_index=True)),
+            ('student_input', self.gf('django.db.models.fields.TextField')(default='', blank=True)),
+            ('created_on', self.gf('django.db.models.fields.DateTimeField')(auto_now_add=True, blank=True)),
+            ('modified_on', self.gf('django.db.models.fields.DateTimeField')(auto_now=True, blank=True)),
+        ))
+        db.send_create_signal('problem_builder', ['Answer'])
+
+        # Adding unique constraint on 'Answer', fields ['student_id', 'course_id', 'name']
+        db.create_unique('problem_builder_answer', ['student_id', 'course_id', 'name'])
+
+    def backwards(self, orm):
+        # Removing unique constraint on 'Answer', fields ['student_id', 'course_id', 'name']
+        db.delete_unique('problem_builder_answer', ['student_id', 'course_id', 'name'])
+
+        # Deleting model 'Answer'
+        db.delete_table('problem_builder_answer')
+
+    models = {
+        'problem_builder.answer': {
+            'Meta': {'unique_together': "(('student_id', 'course_id', 'name'),)", 'object_name': 'Answer'},
+            'course_id': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'created_on': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'modified_on': ('django.db.models.fields.DateTimeField', [], {'auto_now': 'True', 'blank': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'student_id': ('django.db.models.fields.CharField', [], {'max_length': '32', 'db_index': 'True'}),
+            'student_input': ('django.db.models.fields.TextField', [], {'default': "''", 'blank': 'True'})
+        }
+    }
+
+    complete_apps = ['problem_builder']

problem_builder/south_migrations/0002_copy_from_mentoring.py

@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+from django.db.utils import DatabaseError
+from south.db import db
+from south.v2 import DataMigration
+
+
+class Migration(DataMigration):
+
+    def forwards(self, orm):
+        """
+        Copy student data from old table to the new one.
+
+        Problem Builder stores student answers in 'problem_builder_answer'.
+        However earlier versions [may have] used 'mentoring_answer'.
+        If a 'mentoring' app is currently installed on this instance, copy the student data over
+        to the new table in case it is being used.
+        """
+        try:
+            db.execute(
+                'INSERT INTO problem_builder_answer ('
+                'name, student_id, course_id, student_input, created_on, modified_on '
+                ') SELECT '
+                'name, student_id, course_id, student_input, created_on, modified_on '
+                'FROM mentoring_answer'
+            )
+        except DatabaseError:  # Would like to just catch 'Table does not exist' but can't do that in a db-agnostic way
+            print(" - Seems like mentoring_answer does not exist. No data migration needed.")
+
+    def backwards(self, orm):
+        raise RuntimeError("Cannot safely reverse this migration.")
+
+    models = {
+        'problem_builder.answer': {
+            'Meta': {'unique_together': "(('student_id', 'course_id', 'name'),)", 'object_name': 'Answer'},
+            'course_id': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'created_on': ('django.db.models.fields.DateTimeField', [], {'auto_now_add': 'True', 'blank': 'True'}),
+            'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'modified_on': ('django.db.models.fields.DateTimeField', [], {'auto_now': 'True', 'blank': 'True'}),
+            'name': ('django.db.models.fields.CharField', [], {'max_length': '50', 'db_index': 'True'}),
+            'student_id': ('django.db.models.fields.CharField', [], {'max_length': '32', 'db_index': 'True'}),
+            'student_input': ('django.db.models.fields.TextField', [], {'default': "''", 'blank': 'True'})
+        }
+    }
+
+    complete_apps = ['problem_builder']
+    symmetrical = True