backend/app/db/database.py

from typing import AsyncGenerator
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.orm import sessionmaker
from sqlmodel import SQLModel

from app.core.config import settings

# Create Async Engine
# check_same_thread=False is needed only for SQLite. 
connect_args = {"check_same_thread": False} if "sqlite" in settings.DATABASE_URL else {}

engine = create_async_engine(
    settings.DATABASE_URL,
    echo=(settings.LOG_LEVEL == "DEBUG"),
    connect_args=connect_args,
    future=True
)

async def init_db():
    async with engine.begin() as conn:
        # await conn.run_sync(SQLModel.metadata.drop_all)
        await conn.run_sync(SQLModel.metadata.create_all)

async def get_session() -> AsyncGenerator[AsyncSession, None]:
    async_session = sessionmaker(
        engine, class_=AsyncSession, expire_on_commit=False
    )
    async with async_session() as session:
        yield session