CourseOverviews may be deleted, but we don't want to delete related objects

common/djangoapps/course_modes/migrations/0013_auto_20200115_2022.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.27 on 2020-01-15 20:22
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('course_modes', '0012_historicalcoursemode'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='coursemode',
+            name='course',
+            field=models.ForeignKey(db_constraint=False, on_delete=django.db.models.deletion.DO_NOTHING, related_name='modes', to='course_overviews.CourseOverview'),
+        ),
+    ]

common/djangoapps/course_modes/models.py

@@ -54,7 +54,7 @@ class CourseMode(models.Model):
         db_constraint=False,
         db_index=True,
         related_name='modes',
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
     )
 
     # Django sets the `course_id` property in __init__ with the value from the database

common/djangoapps/entitlements/migrations/0014_auto_20200115_2022.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.27 on 2020-01-15 20:22
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('entitlements', '0013_historicalcourseentitlementsupportdetail'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='courseentitlementsupportdetail',
+            name='unenrolled_run',
+            field=models.ForeignKey(blank=True, db_constraint=False, null=True, on_delete=django.db.models.deletion.DO_NOTHING, to='course_overviews.CourseOverview'),
+        ),
+    ]

common/djangoapps/entitlements/models.py

@@ -499,7 +499,7 @@ class CourseEntitlementSupportDetail(TimeStampedModel):
         null=True,
         blank=True,
         db_constraint=False,
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,
     )
 
     history = HistoricalRecords()