Merge pull request #20873 from edx/coryleeio/drop_csm_fk

Drop CSM FK on history

lms/djangoapps/courseware/migrations/0009_auto_20190703_1955.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.22 on 2019-07-03 19:55
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('courseware', '0008_move_idde_to_edx_when'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='studentmodulehistory',
+            name='student_module',
+            field=models.ForeignKey(db_constraint=False, on_delete=django.db.models.deletion.CASCADE, to='courseware.StudentModule'),
+        ),
+    ]

lms/djangoapps/courseware/models.py

@@ -242,7 +242,7 @@ class StudentModuleHistory(BaseStudentModuleHistory):
         app_label = "courseware"
         get_latest_by = "created"
 
-    student_module = models.ForeignKey(StudentModule, db_index=True, on_delete=models.CASCADE)
+    student_module = models.ForeignKey(StudentModule, db_index=True, db_constraint=False, on_delete=models.CASCADE)
 
     def __unicode__(self):
         return unicode(repr(self))