Cache the relation map dictionary

ormar/models/helpers/models.py

@@ -57,9 +57,11 @@ def populate_default_options_values(  # noqa: CCR001
     }
 
     new_model.__relation_map__ = None
+    new_model.__relation_map_dict__ = None
     new_model.__ormar_fields_validators__ = None
 
 
+
 class Connection(sqlite3.Connection):
     def __init__(self, *args: Any, **kwargs: Any) -> None:  # pragma: no cover
         super().__init__(*args, **kwargs)

ormar/models/helpers/validation.py

@@ -42,9 +42,7 @@ def generate_model_example(
     """
     example: Dict[str, Any] = dict()
     relation_map = (
-        relation_map
-        if relation_map is not None
-        else translate_list_to_dict(model._iterate_related_models())
+        relation_map if relation_map is not None else model._related_models_dict()
     )
     for name, field in model.ormar_config.model_fields.items():
         populates_sample_fields_values(

ormar/models/mixins/merge_mixin.py

@@ -87,9 +87,7 @@ def merge_two_instances(
         :rtype: Model
         """
         relation_map = (
-            relation_map
-            if relation_map is not None
-            else translate_list_to_dict(one._iterate_related_models())
+            relation_map if relation_map is not None else one._related_models_dict()
         )
         for field_name in relation_map:
             current_field = getattr(one, field_name)

ormar/models/mixins/relation_mixin.py

@@ -1,7 +1,9 @@
-from typing import TYPE_CHECKING, Callable, Dict, List, Optional, Set, cast
+from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Set, cast
+
 
 from ormar import BaseField, ForeignKeyField
 from ormar.models.traversible import NodeList
+from ormar.queryset.utils import translate_list_to_dict
 
 
 class RelationMixin:
@@ -14,6 +16,7 @@ class RelationMixin:
 
         ormar_config: OrmarConfig
         __relation_map__: Optional[List[str]]
+        __relation_map_dict__: Optional[Dict[str, Any]]
         _related_names: Optional[Set]
         _through_names: Optional[Set]
         _related_fields: Optional[List]
@@ -116,6 +119,13 @@ def _extract_db_related_names(cls) -> Set:
         }
         return related_names
 
+    @classmethod
+    def _related_models_dict(cls) -> dict[str, Any]:
+        if not cls.__relation_map_dict__:
+            cls.__relation_map_dict__ = translate_list_to_dict(cls._iterate_related_models())
+
+        return cls.__relation_map_dict__
+
     @classmethod
     def _iterate_related_models(  # noqa: CCR001
         cls,

ormar/models/model.py

@@ -156,9 +156,7 @@ async def save_related(  # noqa: CCR001, CFQ002
         :rtype: int
         """
         relation_map = (
-            relation_map
-            if relation_map is not None
-            else translate_list_to_dict(self._iterate_related_models())
+            relation_map if relation_map is not None else self._related_models_dict()
         )
         if exclude and isinstance(exclude, Set):
             exclude = translate_list_to_dict(exclude)

ormar/models/newbasemodel.py

@@ -80,6 +80,7 @@ class NewBaseModel(pydantic.BaseModel, ModelTableProxy, metaclass=ModelMetaclass
     if TYPE_CHECKING:  # pragma no cover
         pk: Any
         __relation_map__: Optional[List[str]]
+        __relation_map_dict__: Optional[dict[str, Any]]
         __cached_hash__: Optional[int]
         _orm_relationship_manager: AliasManager
         _orm: RelationsManager
@@ -881,9 +882,7 @@ def model_dump(  # type: ignore # noqa A003
         )
 
         relation_map = (
-            relation_map
-            if relation_map is not None
-            else translate_list_to_dict(self._iterate_related_models())
+            relation_map if relation_map is not None else self._related_models_dict()
         )
         pk_only = getattr(self, "__pk_only__", False)
         if relation_map and not pk_only: