backend/core/database.py

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

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

engine = create_engine(
    settings.DATABASE_URL, 
    connect_args=connect_args
)

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

Base = declarative_base()

def get_db():
    """Dependency for API routes"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()