faster RawDatum bulk-delete (remove downstream CASCADE)

Author: aaxelb

trove/migrations/0007_rawdata_fks_do_nothing.py

@@ -0,0 +1,30 @@
+# Generated by Django 3.2.25 on 2025-04-21 14:59
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('share', '0077_big_cleanup_2025'),
+        ('trove', '0006_supplementary_indexcard_rdf'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='archivedindexcardrdf',
+            name='from_raw_datum',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.DO_NOTHING, related_name='+', to='share.rawdatum'),
+        ),
+        migrations.AlterField(
+            model_name='latestindexcardrdf',
+            name='from_raw_datum',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.DO_NOTHING, related_name='+', to='share.rawdatum'),
+        ),
+        migrations.AlterField(
+            model_name='supplementaryindexcardrdf',
+            name='from_raw_datum',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.DO_NOTHING, related_name='+', to='share.rawdatum'),
+        ),
+    ]

trove/models/indexcard.py

@@ -295,7 +295,7 @@ class IndexcardRdf(models.Model):
     # required:
     from_raw_datum = models.ForeignKey(
         share_db.RawDatum,
-        on_delete=models.CASCADE,
+        on_delete=models.DO_NOTHING,  # allows faster bulk-deletion of unused RawDatum (but errors deleting used RawDatum)
         related_name='+',
     )
     indexcard = models.ForeignKey(