ormodel 0.4.2

An async ORM built on SQLModel with a manager/query API and automatic session handling.

ORModel

Async ORM utilities on top of sqlmodel with a Model.objects manager API and automatic session handling.

What you get

• ORModel base class for models.
• Model.objects manager for query + write operations.
• Async session helpers: init_database, shutdown_database, database_context, get_session.
• SQLModel/SQLAlchemy-native filtering with expressions like Hero.objects.filter(Hero.age >= 18).
• Query chaining (filter, order_by, join, limit, offset) with immutable query objects.
• Auto-session wrapping for manager/query execution methods when no session exists in context.

Requirements

• Python 3.11+
• uv

Install

uv venv .venv
source .venv/bin/activate
uv pip install -e ".[dev]"

Quick start

from sqlmodel import Field
from ormodel import ORModel

class Hero(ORModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str
    secret_name: str

import asyncio
from ormodel import database_context, get_session

async def main() -> None:
    async with database_context("sqlite+aiosqlite:///./example.db"):
        async with get_session():
            hero = await Hero.objects.create(name="Flash", secret_name="Barry")
            same = await Hero.objects.get(id=hero.id)
            print(same)

asyncio.run(main())

Session model

• init_database(...) initializes the async engine/sessionmaker once per process.
• get_session() is the async DB session context manager built on SQLModel/SQLAlchemy AsyncSession, and manages transaction scope:
  • commit on success
  • rollback on exception
• Manager/query methods can run without explicit get_session(); an automatic short-lived session is created when needed.
• For web apps, use request-scoped async with get_session() middleware.
• SQLite gets automatic lock-contention defaults: busy_timeout=30000, foreign_keys=ON, and file-based databases use journal_mode=WAL with synchronous=NORMAL.
• SQLite still allows only one writer at a time. These defaults reduce database is locked failures by waiting longer and using WAL, but they do not make writes fully parallel.

Session modes

• Explicit session mode (async with get_session()): all ORM calls in the block share one session/transaction.
• Auto-session mode (calling manager/query methods without an active context): each call gets its own short-lived session.
• In auto-session mode, returned objects can be detached once the call ends. For relationship access after the call, prefer explicit session mode.

API reference

Model.objects is a Manager. Query-building methods return a Query, and execution methods are async.

Manager (Model.objects)

Method	Returns	Notes
all()	Sequence[Model]	Fetch all rows for model.
first()	Model | None	First row or None.
one()	Model	Exactly one row; raises on 0 or >1.
one_or_none()	Model | None	None on 0 rows; raises on >1.
get(*expr, **filters)	Model	Single row lookup; raises DoesNotExist / MultipleObjectsReturned.
filter(*expr, **filters)	Query[Model]	Build filtered query.
order_by(*columns)	Query[Model]	Build ordered query.
limit(n)	Query[Model]	Build limited query.
offset(n)	Query[Model]	Build offset query.
join(target)	Query[Model]	Build joined query.
count()	int	Count rows.
update(**values)	int	Bulk update matching rows; returns affected row count.
create(**values)	Model	Validate + insert + refresh one row.
get_or_create(defaults=None, **filters)	tuple[Model, bool]	(obj, created); creates if not found.
update_or_create(defaults=None, **filters)	tuple[Model, bool]	(obj, created); updates found row or creates new row.
delete()	int	Bulk-delete all rows for this model.
bulk_create(list[Model])	list[Model]	Insert many instances with session.add_all.

Query (Model.objects.filter(...))

Method	Returns	Notes
filter(*expr, **filters)	Query[Model]	Add WHERE clauses (*expr for SQL expressions, **filters for exact field equality only).
order_by(*columns)	Query[Model]	Add ordering.
limit(n)	Query[Model]	Add SQL LIMIT.
offset(n)	Query[Model]	Add SQL OFFSET.
join(target)	Query[Model]	Add SQL JOIN.
all()	Sequence[Model]	Execute and return all rows.
first()	Model | None	Execute and return first row.
one()	Model	Execute expecting exactly one row.
one_or_none()	Model | None	Execute expecting <=1 row.
get(*expr, **filters)	Model	Shortcut for filter(...).one().
count()	int	Count matching rows.
update(**values)	int	Bulk update matching rows.
delete()	int	Bulk delete matching rows.

Comparison filters use SQL expressions:

adults = await Hero.objects.filter(Hero.age > 18).all()
teens = await Hero.objects.filter(Hero.age >= 13, Hero.age < 20).all()

Keyword filters remain exact-match only:

exact_18 = await Hero.objects.filter(age=18).all()

Model instance methods (ORModel)

Method	Returns	Notes
save()	Self	Insert/update current instance and refresh it.
delete()	None	Delete current instance.

Database/session helpers

Function	Returns	Notes
init_database(database_url, echo_sql=False)	None	Initialize engine + sessionmaker.
shutdown_database()	None	Dispose engine and clear factory.
database_context(database_url, echo_sql=False)	async context manager	Convenience wrapper for init/shutdown in scripts.
get_session()	async context manager	Transaction scope: commit on success, rollback on error.
get_engine()	AsyncEngine	Access initialized engine.
get_session_from_context()	AsyncSession	Get current context session; raises if absent.

Exceptions

Exception	When raised
DoesNotExist	A query expected one row and found none.
MultipleObjectsReturned	A query expected one row and found more than one.
SessionContextError	A session was required but none exists in context.

FastAPI integration pattern

Use lifespan for DB lifecycle and a route-level dependency for DB transaction scope:

from collections.abc import AsyncGenerator
from contextlib import asynccontextmanager
from fastapi import Depends, FastAPI
from ormodel import init_database, shutdown_database, get_session

@asynccontextmanager
async def lifespan(app: FastAPI):
    init_database("sqlite+aiosqlite:///./example.db")
    yield
    await shutdown_database()

app = FastAPI(lifespan=lifespan)

async def db_session_scope() -> AsyncGenerator[None, None]:
    async with get_session():
        yield

@app.get("/heroes", dependencies=[Depends(db_session_scope)])
async def read_heroes():
    return await Hero.objects.all()

If your app genuinely needs DB scope for every request, use middleware instead:

from fastapi import Request

@app.middleware("http")
async def db_session_middleware(request: Request, call_next):
    async with get_session():
        return await call_next(request)

Repository Pattern Example

You can keep data access in repository classes and keep business logic in services. See the complete runnable example in:

• examples/repository_pattern.py

Minimal shape:

class HeroRepository:
    async def create(self, **data) -> Hero:
        return await Hero.objects.create(**data)

    async def list_adults(self) -> list[Hero]:
        return list(await Hero.objects.filter(Hero.age >= 18).order_by(Hero.name).all())

class HeroService:
    def __init__(self, heroes: HeroRepository):
        self.heroes = heroes

    async def register(self, name: str, secret_name: str, age: int) -> Hero:
        return await self.heroes.create(name=name, secret_name=secret_name, age=age)

Usage:

async with database_context("sqlite+aiosqlite:///./example.db"):
    async with get_session():
        service = HeroService(HeroRepository())
        await service.register("Flash", "Barry Allen", 28)

Commands (consistent uv run style)

From repository root:

• Run examples as modules (for example, python -m examples.standalone), not as direct files.
• Run tests: uv run pytest -v
• Run tests with coverage: uv run pytest --cov=ormodel --cov-branch --cov-report=xml
• Run API example: uv run python -m examples.api
• Run standalone example: uv run python -m examples.standalone
• Run repository-pattern example: uv run python -m examples.repository_pattern
• Run alembic in examples: cd examples && uv run alembic upgrade head

Development notes

• Tests use SQLite via configured DATABASE_URL (default in pyproject.toml is sqlite+aiosqlite:///./default.db) and recreate schema per test.
• Package exports live in ormodel/__init__.py.

License

MIT