Protect some objects from deletion

server/assignments/schema/types.py

@@ -56,7 +56,6 @@ class AssignmentNode(DjangoObjectType):
     def resolve_submission(self, info, **kwargs):
         return self.submissions.filter(student=info.context.user).first()  #  returns None if it doesn't exist yet
 
-    #todo: restrict for students
     def resolve_submissions(self, info, **kwargs):
         user = info.context.user
         if user.has_perm('users.can_manage_school_class_content'):

server/objectives/migrations/0012_auto_20210210_1109.py

@@ -0,0 +1,25 @@
+# Generated by Django 2.2.17 on 2021-02-10 11:09
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('objectives', '0011_auto_20210121_1857'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='objective',
+            name='owner',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AlterField(
+            model_name='objectivegroup',
+            name='owner',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL),
+        ),
+    ]

server/objectives/models.py

@@ -24,7 +24,7 @@ class ObjectiveGroup(models.Model):
     title = models.CharField('title', blank=True, null=False, max_length=255, choices=TITLE_CHOICES, default=LANGUAGE_COMMUNICATION)
     module = models.ForeignKey(Module, blank=False, null=False, on_delete=models.CASCADE, related_name='objective_groups')
     # a user can define her own objectives, hence this optional param
-    owner = models.ForeignKey(get_user_model(), blank=True, null=True, on_delete=models.CASCADE)
+    owner = models.ForeignKey(get_user_model(), blank=True, null=True, on_delete=models.PROTECT)
 
     hidden_for = models.ManyToManyField(SchoolClass, related_name='hidden_objective_groups', blank=True)
     visible_for = models.ManyToManyField(SchoolClass, related_name='visible_objective_groups', blank=True)
@@ -42,7 +42,7 @@ class Objective(models.Model):
     text = models.CharField('text', blank=True, null=False, max_length=255)
     group = models.ForeignKey(ObjectiveGroup, blank=False, null=False, on_delete=models.CASCADE,
                               related_name='objectives')
-    owner = models.ForeignKey(get_user_model(), blank=True, null=True, on_delete=models.CASCADE)
+    owner = models.ForeignKey(get_user_model(), blank=True, null=True, on_delete=models.PROTECT)
     hidden_for = models.ManyToManyField(SchoolClass, related_name='hidden_objectives', blank=True)
     visible_for = models.ManyToManyField(SchoolClass, related_name='visible_objectives', blank=True)
     order = models.IntegerField(null=True, blank=True)
@@ -51,6 +51,7 @@ class Objective(models.Model):
         return 'Objective {}-{}'.format(self.id, self.text)
 
 
+# todo: delete
 class ObjectiveProgressStatus(models.Model):
     class Meta:
         verbose_name = 'Lernzielstatus'