fixup! Store subdivided areas.

mapit/models.py

@@ -6,7 +6,6 @@
 from django.contrib.gis.db import models
 from django.conf import settings
 from django.db import connection
-from django.db.models import F, Func
 from django.db.models.query import RawQuerySet
 from django.utils.encoding import smart_str
 from django.utils.functional import cached_property
@@ -336,9 +335,10 @@ def __str__(self):
 
     def save(self, *args, **kwargs):
         super().save(*args, **kwargs)
-        divided = Geometry.objects.filter(id=self.id).annotate(division=Func(F('polygon'), function='ST_Subdivide'))
         GeometrySubdivided.objects.filter(geometry=self).delete()
-        GeometrySubdivided.objects.bulk_create(GeometrySubdivided(geometry=self, division=p.division) for p in divided)
+        with connection.cursor() as cursor:
+            cursor.execute('''INSERT INTO mapit_geometrysubdivided (geometry_id, division)
+                SELECT id,ST_Subdivide(polygon) FROM mapit_geometry WHERE id = %s''', [self.id])
 
 
 class GeometrySubdivided(models.Model):