Refs #12400 -- Added supports_geometry_field_unique_index GIS db feature.

django/contrib/gis/db/backends/base/features.py

@@ -40,6 +40,9 @@ class BaseSpatialFeatures(object):
     # Does the database have raster support?
     supports_raster = False
 
+    # Does the database support a unique index on geometry fields?
+    supports_geometry_field_unique_index = True
+
     @property
     def supports_bbcontains_lookup(self):
         return 'bbcontains' in self.connection.ops.gis_operators

django/contrib/gis/db/backends/oracle/features.py

@@ -6,3 +6,4 @@ from django.db.backends.oracle.features import \
 class DatabaseFeatures(BaseSpatialFeatures, OracleDatabaseFeatures):
     supports_add_srs_entry = False
     supports_geometry_field_introspection = False
+    supports_geometry_field_unique_index = False

tests/gis_tests/geoapp/models.py

@@ -63,7 +63,7 @@ class MultiFields(NamedModel):
 
     class Meta:
         unique_together = ('city', 'point')
-        required_db_features = ['gis_enabled']
+        required_db_features = ['gis_enabled', 'supports_geometry_field_unique_index']
 
 
 class Truth(models.Model):