ISBN is unique

media/migrations/0026_auto_20200210_1740.py

@@ -0,0 +1,20 @@
+# Generated by Django 2.2.4 on 2020-02-10 16:40
+
+from django.db import migrations
+import media.fields
+import media.validators
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('media', '0025_auteur_note'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='media',
+            name='isbn',
+            field=media.fields.ISBNField(blank=True, help_text='You may be able to scan it from a bar code.', max_length=28, null=True, unique=True, validators=[media.validators.isbn_validator], verbose_name='ISBN'),
+        ),
+    ]

media/models.py

@@ -34,6 +34,7 @@ class Media(models.Model):
     isbn = ISBNField(
         _('ISBN'),
         help_text=_('You may be able to scan it from a bar code.'),
+        unique=True,
         blank=True,
         null=True,
     )