INTPYTHON-348 Add support for QuerySet.raw()

- Fix MongoRawModelIterable

Author: aclark4life

django_mongodb/query.py

@@ -368,30 +368,48 @@ def iterator(self):
 
 
 class MongoRawModelIterable(RawModelIterable):
+    """
+    Iterable that yields a model instance for each row from a raw queryset.
+    """
 
     def __iter__(self):
+        # Cache some things for performance reasons outside the loop.
         db = self.queryset.db
         query = self.queryset.query
         connection = connections[db]
         compiler = connection.ops.compiler("SQLCompiler")(query, connection, db)
-        query_iterator = iter(query)
+        query_iterator = self._make_result(query)
+
         try:
             (
                 model_init_names,
                 model_init_pos,
                 annotation_fields,
             ) = self.queryset.resolve_model_init_order()
             model_cls = self.queryset.model
+            if model_cls._meta.pk.attname not in model_init_names:
+                raise exceptions.FieldDoesNotExist(
+                    "Raw query must include the primary key"
+                )
             fields = [self.queryset.model_fields.get(c) for c in self.queryset.columns]
             converters = compiler.get_converters(
                 [f.get_col(f.model._meta.db_table) if f else None for f in fields]
             )
             if converters:
                 query_iterator = compiler.apply_converters(query_iterator, converters)
             for values in query_iterator:
-                model_init_values = values.values()
+                # Associate fields to values
+                model_init_values = [values[pos] for pos in model_init_pos]
                 instance = model_cls.from_db(db, model_init_names, model_init_values)
+                if annotation_fields:
+                    for column, pos in annotation_fields:
+                        setattr(instance, column, values[pos])
                 yield instance
         finally:
+            # Done iterating the Query. If it has its own cursor, close it.
             if hasattr(query, "cursor") and query.cursor:
                 query.cursor.close()
+
+    def _make_result(self, query):
+        for result in query:
+            yield list(result.values())