# Parcel duplicate repair

* adds mechanic to repair parcels in case of unwanted parcel duplicates
* optimizes filtering of geometries for parcel recalculation

konova/management/commands/recalculate_parcels.py

@@ -8,11 +8,9 @@ Created on: 04.01.22
 import datetime
 
 from django.contrib.gis.db.models.functions import Area
-from django.db.models import Q
-from django.utils.timezone import now
 
 from konova.management.commands.setup import BaseKonovaCommand
-from konova.models import Geometry
+from konova.models import Geometry, ParcelIntersection
 
 
 class Command(BaseKonovaCommand):
@@ -36,17 +34,21 @@ class Command(BaseKonovaCommand):
     def recalculate_parcels(self, options: dict):
         force_all = options.get("force_all", False)
 
-        if force_all:
-            geometry_objects = Geometry.objects.all()
-        else:
-            _today = now().date()
-            _date_threshold = _today - datetime.timedelta(days=1)
-            geometry_objects = Geometry.objects.filter(
-                Q(
-                    Q(parcel_update_start__date__lte=_date_threshold) |
-                    Q(parcel_update_start__isnull=True)
-                ),
-                parcel_update_end__isnull=True
+        geometry_objects = Geometry.objects.all()
+
+        if not force_all:
+            # Fetch all intersections
+            intersection_objs = ParcelIntersection.objects.filter(
+                geometry__in=geometry_objects
+            )
+            # Just take the geometry ids, which seem to have intersections
+            geom_with_intersection_ids = intersection_objs.values_list(
+                "geometry__id",
+                flat=True
+            )
+            # Filter those geometries out (they have intersections and do not need to be processed)
+            geometry_objects = geometry_objects.exclude(
+                id__in=geom_with_intersection_ids
             )
 
         self._write_warning("=== Update parcels and districts ===")

konova/models/geometry.py

@@ -8,7 +8,7 @@ Created on: 15.11.21
 import json
 
 from django.contrib.gis.db.models import MultiPolygonField
-from django.core.exceptions import ObjectDoesNotExist
+from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned
 from django.db import models, transaction
 from django.utils import timezone
 
@@ -223,6 +223,17 @@ class Geometry(BaseResource):
                 )
                 parcel_obj.updated_on = _now
                 parcels_to_update.append(parcel_obj)
+            except MultipleObjectsReturned:
+                parcel_obj = Parcel.make_unique(
+                    district=district,
+                    municipal=municipal,
+                    parcel_group=parcel_group,
+                    flr=flr_val,
+                    flrstck_nnr=flrstck_nnr,
+                    flrstck_zhlr=flrstck_zhlr,
+                )
+                parcel_obj.updated_on = _now
+                parcels_to_update.append(parcel_obj)
             except ObjectDoesNotExist:
                 # If not existing, create object but do not commit, yet
                 parcel_obj = Parcel(

konova/models/parcel.py

@@ -5,7 +5,7 @@ Contact: michel.peltriaux@sgdnord.rlp.de
 Created on: 16.12.21
 
 """
-from django.db import models
+from django.db import models, transaction
 
 from konova.models import UuidModel
 
@@ -158,6 +158,46 @@ class Parcel(UuidModel):
     def __str__(self):
         return f"{self.parcel_group} | {self.flr} | {self.flrstck_zhlr} | {self.flrstck_nnr}"
 
+    @classmethod
+    @transaction.atomic
+    def make_unique(cls, **kwargs):
+        """ Checks for duplicates of a Parcel, choose a (now) unique one,
+        repairs relations for ParcelIntersection and removes duplicates.
+
+        Args:
+            **kwargs ():
+
+        Returns:
+            unique_true (Parcel): The new unique 'true one'
+        """
+        parcel_objs = Parcel.objects.filter(**kwargs)
+
+        if not parcel_objs.exists():
+            return None
+
+        # Get one of the found parcels and use it as new 'true one'
+        unique_parcel = parcel_objs.first()
+        # separate it from the rest
+        parcel_objs = parcel_objs.exclude(id=unique_parcel.id)
+
+        if not parcel_objs.exists():
+            # There are no duplicates - all good, just return
+            return unique_parcel
+
+        # Fetch existing intersections, which still point on the duplicated parcels
+        intersection_objs = ParcelIntersection.objects.filter(
+            parcel__in=parcel_objs
+        )
+        # Change each intersection, so they point on the 'true one' parcel from now on
+        for intersection in intersection_objs:
+            intersection.parcel = unique_parcel
+            intersection.save()
+
+        # Remove the duplicated parcels
+        parcel_objs.delete()
+
+        return unique_parcel
+
 
 class ParcelIntersection(UuidModel):
     """