Release 1.3.0

This release introduces a Django-like way to eliminate N+1 queries: an inner RelatedConfig class on Pydantic schemas that tells the ORM adapter which relationships to eager-load on LIST and GET endpoints.

Highlights

Declarative eager loading via RelatedConfig

• Add select_related = [...] (FK / many-to-one) and/or prefetch_related = [...] (collections / many-to-many) to a Pydantic schema's inner RelatedConfig class.
• When the schema is used as response_model in a viewset, BaseViewset and AsyncBaseViewset automatically forward these lists to the ORM adapter so relationships are loaded in a single (or minimal) round-trip.
• No changes in the viewset itself are required — configuration lives in the schema, next to the fields it describes.

Example:

class PostSchema(BaseModel):
    model_config = ConfigDict(from_attributes=True)
    id: int
    title: str
    author: AuthorSchema          # nested → needs join

    class RelatedConfig:
        select_related = ["author"]   # SQLAlchemy: joinedload
        prefetch_related = ["tags"]   # SQLAlchemy: selectinload

posts = AsyncBaseViewset(
    endpoint="/posts",
    model=Post,
    response_model=PostSchema,
    db_session=get_async_session,
)

Adapter-level support

ORM	select_related	prefetch_related	Implementation
SQLAlchemy (sync)	✅	✅	joinedload / selectinload on Query
SQLAlchemy (async)	✅	✅	joinedload / selectinload on select() + result.unique()
Tortoise ORM	✅*	✅	prefetch_related() for both (*Tortoise has no separate select_related)
Peewee	✅	—	.join() for select_related

• All adapter methods (get_list_queryset, get_list_queryset_async, get_element_by_id, get_element_by_id_async) accept optional select_related and prefetch_related keyword arguments for explicit overrides.
• The low-level utilities in fastapi_viewsets.utils and fastapi_viewsets.async_utils also accept these arguments, plus an optional response_model. When response_model is provided and the explicit lists are omitted, the utilities read them automatically from RelatedConfig.

Backward compatibility

• Every new parameter defaults to None. Existing code, tests and subclassed viewsets continue to work without any changes.
• The public API surface of BaseViewset and AsyncBaseViewset is unchanged; only the internal calls to the ORM adapters now forward additional optional kwargs.

Internal additions

• fastapi_viewsets.serializer_utils — small helper module that extracts select_related and prefetch_related from a Pydantic model's RelatedConfig inner class.

Tests

• 258+ tests pass (219 new/legacy + 39 skipped for optional ORMs).
• Coverage remains above the 70% gate.
• New dedicated test file: tests/test_select_prefetch_related.py covering serializer_utils, SQLAlchemy sync/async adapters, and the integration between utils / async_utils with RelatedConfig.

Upgrade

pip install -U fastapi-viewsets==1.3.0

No code changes are required for existing users. To opt into eager loading, add a RelatedConfig class to the Pydantic schemas you already pass as response_model.