aichat_app/backend/app/core/database.py

"""
数据库连接管理
"""
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from app.core.config import settings

# 异步引擎（用于FastAPI）
async_engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    pool_pre_ping=True,
    pool_size=10,
    max_overflow=20,
)

# 异步会话工厂
AsyncSessionLocal = async_sessionmaker(
    async_engine,
    class_=AsyncSession,
    expire_on_commit=False,
)

# 同步引擎（用于Alembic迁移）
sync_engine = create_engine(
    settings.DATABASE_URL_SYNC,
    echo=settings.DEBUG,
    pool_pre_ping=True,
)

# 同步会话工厂
SessionLocal = sessionmaker(
    autocommit=False,
    autoflush=False,
    bind=sync_engine,
)

# 基础模型类
Base = declarative_base()


async def get_db() -> AsyncSession:
    """
    获取数据库会话（依赖注入）
    """
    async with AsyncSessionLocal() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()