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

# SQLAlchemy 2.0 style
engine = create_engine(
    settings.DATABASE_URI,
    pool_pre_ping=True,
    echo=False,
    pool_size=20,       # 增加连接池大小
    max_overflow=40     # 允许溢出更多连接
)

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

Base = declarative_base()

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