misc: migrate map/layers many to many table (#...)

combo/apps/maps/migrations/0008_auto_20180108_1731.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('maps', '0007_auto_20180107_1355'),
+    ]
+
+    operations = [
+        migrations.RunSQL("""
+            UPDATE maps_map_layers SET map_id =
+                    (SELECT data_cellbase.id
+                       FROM data_cellbase
+                      WHERE data_cellbase.subclassid = maps_map_layers.map_id
+                        AND data_cellbase.subclass = 27);"""),
+    ]