Change ParentalKey relation back to old ForeignKey to prevent deletion

server/assignments/migrations/0018_alter_assignment_module.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.2.16 on 2023-05-04 12:14
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('books', '0042_alter_contentblock_contents'),
+        ('assignments', '0017_alter_assignment_module'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='assignment',
+            name='module',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='assignments', to='books.module'),
+        ),
+    ]

server/assignments/models.py

@@ -21,7 +21,7 @@ class Assignment(index.Indexed, TimeStampedModel):
     owner = models.ForeignKey(
         get_user_model(), on_delete=models.PROTECT, null=True, blank=True
     )  # probably don't want to delete all assignments if a user gets deleted
-    module = ParentalKey(
+    module = models.ForeignKey(
         "books.Module", related_name="assignments", on_delete=models.PROTECT
     )
     user_created = models.BooleanField(default=False)

server/surveys/migrations/0008_alter_survey_module.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.2.16 on 2023-05-04 12:14
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('books', '0042_alter_contentblock_contents'),
+        ('surveys', '0007_alter_survey_module'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='survey',
+            name='module',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, related_name='surveys', to='books.module'),
+        ),
+    ]

server/surveys/models.py

@@ -9,7 +9,7 @@ from modelcluster.fields import ParentalKey
 @register_snippet
 class Survey(models.Model, index.Indexed):
     title = models.CharField(max_length=255)
-    module = ParentalKey(
+    module = models.ForeignKey(
         "books.Module",
         related_name="surveys",
         on_delete=models.PROTECT,