app/database.py

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base
from app.config import settings

# SQLiteかどうか検知
is_sqlite = settings.DATABASE_URL.startswith("sqlite+")

engine = create_engine(
    settings.DATABASE_URL,
    pool_pre_ping=not is_sqlite,
    future=True,
    connect_args={"check_same_thread": False} if is_sqlite else {},
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine, future=True)
Base = declarative_base()

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()