app/db/database.py

from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from app.core.config import settings

DATABASE_URL = settings.DATABASE_URL

if DATABASE_URL.startswith("sqlite"):
    engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})
else:
    if DATABASE_URL.startswith("postgres://"):
        DATABASE_URL = DATABASE_URL.replace("postgres://", "postgresql://", 1)
    engine = create_engine(DATABASE_URL)

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