implement SchemaEditor.alter_index_together()

Author: timgraham

django_mongodb/schema.py

@@ -202,6 +202,30 @@ def _remove_field_index(self, model, field):
             )
         collection.drop_index(index_names[0])
 
+    def _remove_composed_index(self, model, field_names, constraint_kwargs):
+        """
+        Remove the index on the given list of field_names created by
+        index/unique_together, depending on constraint_kwargs.
+        """
+        meta_constraint_names = {constraint.name for constraint in model._meta.constraints}
+        meta_index_names = {constraint.name for constraint in model._meta.indexes}
+        columns = [model._meta.get_field(field).column for field in field_names]
+        constraint_names = self._constraint_names(
+            model,
+            columns,
+            exclude=meta_constraint_names | meta_index_names,
+            **constraint_kwargs,
+        )
+        if len(constraint_names) != 1:
+            num_found = len(constraint_names)
+            columns_str = ", ".join(columns)
+            raise ValueError(
+                f"Found wrong number ({num_found}) of constraints for "
+                f"{model._meta.db_table}({columns_str})."
+            )
+        collection = self.connection.database[model._meta.db_table]
+        collection.drop_index(constraint_names[0])
+
     def add_constraint(self, model, constraint):
         pass