set null

test_server/examtest/migrations/0023_auto_20200402_2346.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.0.4 on 2020-04-02 15:46
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('examtest', '0022_auto_20200402_2313'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='paper',
+            name='workscope',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to='examtest.WorkScope', verbose_name='名称'),
+        ),
+    ]

test_server/examtest/models_paper.py

@@ -26,7 +26,7 @@ class TestRule(SoftCommonModel):
     def __str__(self):
         return self.name
 
-class WorkScope(SoftCommonModel):
+class WorkScope(CommonModel):
     name = models.CharField(max_length=200, unique=True, verbose_name='名称')
     subject = models.ForeignKey(Questioncat, verbose_name='所属学科', on_delete=models.CASCADE , related_name='workscope_subject')
     questioncat = models.ManyToManyField(Questioncat, verbose_name='所选科目')
@@ -41,7 +41,7 @@ class WorkScope(SoftCommonModel):
 
 class Paper(SoftCommonModel):
     name = models.CharField(max_length=200, verbose_name='名称')
-    workscope = models.ForeignKey(WorkScope, on_delete=models.CASCADE, null=True, blank=True, verbose_name='名称')
+    workscope = models.ForeignKey(WorkScope, on_delete=models.SET_NULL, null=True, blank=True, verbose_name='名称')
     questions = models.ManyToManyField(Question, through='PaperQuestions')
     limit = models.IntegerField(default=0, verbose_name='限时(分钟)')
     total_score = models.FloatField(default=0, verbose_name='满分')

test_server/question/migrations/0010_auto_20200402_2346.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.0.4 on 2020-04-02 15:46
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('question', '0009_auto_20200402_2313'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='question',
+            name='questioncat',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='questioncat', to='question.Questioncat', verbose_name='所属题库'),
+        ),
+    ]