add helper for index creation

Author: timgraham

django_mongodb/schema.py

@@ -22,9 +22,7 @@ def _create_model_indexes(self, model):
         # Field indexes
         for field in model._meta.local_fields:
             if self._field_should_be_indexed(model, field):
-                index = Index(fields=[field.name])
-                index.name = self._create_index_name(model._meta.db_table, [field.column])
-                self.add_index(model, index)
+                self._add_index_for_field(model, field)
         # Meta.index_together (RemovedInDjango51Warning)
         for field_names in model._meta.index_together:
             index = Index(fields=field_names)
@@ -53,11 +51,15 @@ def add_field(self, model, field):
             )
         # Add an index, if required.
         if self._field_should_be_indexed(model, field):
-            index = Index(fields=[field.name])
-            index.name = self._create_index_name(model._meta.db_table, [field.column])
-            self.add_index(model, index, field=field)
+            self._add_index_for_field(model, field)
 
-    def _drop_index_for_field(self, collection, model, field):
+    def _add_index_for_field(self, model, field):
+        new_index = Index(fields=[field.name])
+        new_index.name = self._create_index_name(model._meta.db_table, [field.column])
+        self.add_index(model, new_index, field=field)
+
+    def _drop_index_for_field(self, model, field):
+        collection = self.connection.database[model._meta.db_table]
         # Find the index for this field
         meta_index_names = {index.name for index in model._meta.indexes}
         # Retrieve only BTREE indexes since this is what's created with
@@ -104,18 +106,16 @@ def _alter_field(
             and not old_field.unique
             and (not new_field.db_index or new_field.unique)
         ):
-            self._drop_index_for_field(collection, model, old_field)
+            self._drop_index_for_field(model, old_field)
         # Have they renamed the column?
         if old_field.column != new_field.column:
             collection.update_many({}, {"$rename": {old_field.column: new_field.column}})
             # Move index to the new field, if needed.
-            if self._field_should_be_indexed(model, old_field) and self.__field_should_be_indexed(
+            if self._field_should_be_indexed(model, old_field) and self._field_should_be_indexed(
                 model, new_field
             ):
-                self._drop_index_for_field(collection, model, old_field)
-                new_index = Index(fields=[new_field.name])
-                new_index.name = self._create_index_name(model._meta.db_table, [new_field.column])
-                self.add_index(model, new_index, field=new_field)
+                self._drop_index_for_field(model, old_field)
+                self._add_index_for_field(model, new_field)
         # Replace NULL with the field default if the field and was changed from
         # NULL to NOT NULL.
         if new_field.has_default() and old_field.null and not new_field.null:
@@ -136,9 +136,7 @@ def _alter_field(
             and new_field.db_index
             and not new_field.unique
         ):
-            index = Index(fields=[new_field.name])
-            index.name = self._create_index_name(model._meta.db_table, [new_field.column])
-            self.add_index(model, index)
+            self._add_index_for_field(model, new_field)
 
     def remove_field(self, model, field):
         # Remove implicit M2M tables.