SQLAlchemy Plugin

The SQLAlchemyPlugin provides complete support for working with SQLAlchemy in Litestar applications.

Note

This plugin is only compatible with SQLAlchemy 2.0+.

The SQLAlchemyPlugin combines the functionality of SQLAlchemyInitPlugin and SQLAlchemySerializationPlugin, each of which are examined in detail in the following sections. As such, this section describes a complete example of using the SQLAlchemyPlugin with a Litestar application and a SQLite database.

Or, skip ahead to SQLAlchemy Init Plugin or SQLAlchemy Serialization Plugin to learn more about the individual plugins.

Tip

You can install SQLAlchemy alongside Litestar by running pip install litestar[sqlalchemy].

Example

Async

SQLAlchemy Async Plugin Example

from __future__ import annotations

from collections.abc import Sequence
from typing import TYPE_CHECKING

from sqlalchemy import select
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column

from litestar import Litestar, post
from litestar.plugins.sqlalchemy import SQLAlchemyAsyncConfig, SQLAlchemyPlugin

if TYPE_CHECKING:
    from sqlalchemy.ext.asyncio import AsyncSession


class Base(DeclarativeBase): ...


class TodoItem(Base):
    __tablename__ = "todo_item"
    title: Mapped[str] = mapped_column(primary_key=True)
    done: Mapped[bool]


@post("/")
async def add_item(data: TodoItem, db_session: AsyncSession) -> Sequence[TodoItem]:
    async with db_session.begin():
        db_session.add(data)
    return (await db_session.execute(select(TodoItem))).scalars().all()


config = SQLAlchemyAsyncConfig(
    connection_string="sqlite+aiosqlite:///todo_async.sqlite", create_all=True, metadata=Base.metadata
)
plugin = SQLAlchemyPlugin(config=config)
app = Litestar(route_handlers=[add_item], plugins=[plugin])

Sync

SQLAlchemy Sync Plugin Example

from __future__ import annotations

from collections.abc import Sequence
from typing import TYPE_CHECKING

from sqlalchemy import select
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column

from litestar import Litestar, post
from litestar.plugins.sqlalchemy import SQLAlchemyPlugin, SQLAlchemySyncConfig

if TYPE_CHECKING:
    from sqlalchemy.orm import Session


class Base(DeclarativeBase): ...


class TodoItem(Base):
    __tablename__ = "todo_item"
    title: Mapped[str] = mapped_column(primary_key=True)
    done: Mapped[bool]


@post("/", sync_to_thread=True)
def add_item(data: TodoItem, db_session: Session) -> Sequence[TodoItem]:
    with db_session.begin():
        db_session.add(data)
    return db_session.execute(select(TodoItem)).scalars().all()


config = SQLAlchemySyncConfig(connection_string="sqlite:///todo_sync.sqlite", create_all=True, metadata=Base.metadata)
plugin = SQLAlchemyPlugin(config=config)
app = Litestar(route_handlers=[add_item], plugins=[plugin])

Defining the Database Models

We start by defining our base model class, and a TodoItem class which extends the base model. The TodoItem class represents a todo item in our SQLite database.

Async

SQLAlchemy Async Plugin Example

class Base(DeclarativeBase): ...


class TodoItem(Base):
    __tablename__ = "todo_item"
    title: Mapped[str] = mapped_column(primary_key=True)
    done: Mapped[bool]

Sync

SQLAlchemy Sync Plugin Example

class Base(DeclarativeBase): ...


class TodoItem(Base):
    __tablename__ = "todo_item"
    title: Mapped[str] = mapped_column(primary_key=True)
    done: Mapped[bool]

Setting Up an API Endpoint

Next, we set up an API endpoint at the root ("/") that allows adding a TodoItem to the SQLite database.

Async

SQLAlchemy Async Plugin Example

from collections.abc import Sequence
from typing import TYPE_CHECKING



if TYPE_CHECKING:
    from sqlalchemy.ext.asyncio import AsyncSession

@post("/")
async def add_item(data: TodoItem, db_session: AsyncSession) -> Sequence[TodoItem]:
    async with db_session.begin():
        db_session.add(data)
    return (await db_session.execute(select(TodoItem))).scalars().all()

Sync

SQLAlchemy Sync Plugin Example

from collections.abc import Sequence
from typing import TYPE_CHECKING



if TYPE_CHECKING:
    from sqlalchemy.orm import Session

@post("/", sync_to_thread=True)
def add_item(data: TodoItem, db_session: Session) -> Sequence[TodoItem]:
    with db_session.begin():
        db_session.add(data)
    return db_session.execute(select(TodoItem)).scalars().all()

Initializing the Database

We create a function init_db that we’ll use to initialize the database when the app starts up.

Important

In this example we drop the database before creating it. This is done for the sake of repeatability, and should not be done in production.

Async

SQLAlchemy Async Plugin Example

config = SQLAlchemyAsyncConfig(
    connection_string="sqlite+aiosqlite:///todo_async.sqlite", create_all=True, metadata=Base.metadata
)
plugin = SQLAlchemyPlugin(config=config)

Sync

SQLAlchemy Sync Plugin Example

config = SQLAlchemySyncConfig(connection_string="sqlite:///todo_sync.sqlite", create_all=True, metadata=Base.metadata)
plugin = SQLAlchemyPlugin(config=config)

Setting Up the Plugin and the App

Finally, we set up the SQLAlchemy Plugin and the Litestar app.

Async

SQLAlchemy Async Plugin Example

config = SQLAlchemyAsyncConfig(
    connection_string="sqlite+aiosqlite:///todo_async.sqlite", create_all=True, metadata=Base.metadata
)
plugin = SQLAlchemyPlugin(config=config)

Sync

SQLAlchemy Sync Plugin Example

config = SQLAlchemySyncConfig(connection_string="sqlite:///todo_sync.sqlite", create_all=True, metadata=Base.metadata)
plugin = SQLAlchemyPlugin(config=config)

This configures the app with the plugin, sets up a route handler for adding items, and specifies that the init_db function should be run when the app starts up.

Running the App

Run the app with the following command:

$ litestar run

You can now add a todo item by sending a POST request to http://localhost:8000 with a JSON body containing the "title" of the todo item.

$ curl -X POST -H "Content-Type: application/json" -d '{"title": "Your Todo Title", "done": false}' http://localhost:8000/