pip install aiohttp-sqlalchemy

pip install aiosqlite

from datetime import datetime

import sqlalchemy as sa
from aiohttp import web
from sqlalchemy import orm

import aiohttp_sqlalchemy as ahsa

metadata = sa.MetaData()
Base = orm.declarative_base(metadata=metadata)


class MyModel(Base):
    __tablename__ = 'my_table'

    pk = sa.Column(sa.Integer, primary_key=True)
    timestamp = sa.Column(sa.DateTime(), default=datetime.now)


async def main(request):
    sa_session = ahsa.get_session(request)

    async with sa_session.begin():
        sa_session.add(MyModel())
        result = await sa_session.execute(sa.select(MyModel))
        result = result.scalars()

    data = {
        instance.pk: instance.timestamp.isoformat()
        for instance in result
    }
    return web.json_response(data)


async def app_factory():
    app = web.Application()

    ahsa.setup(app, [
        ahsa.bind('sqlite+aiosqlite:///'),
    ])
    await ahsa.init_db(app, metadata)

    app.add_routes([web.get('/', main)])
    return app


if __name__ == '__main__':
    web.run_app(app_factory())