init

server/app/db/base.py

@@ -0,0 +1,6 @@
+from sqlalchemy.orm import DeclarativeBase
+
+
+class Base(DeclarativeBase):
+    """SQLAlchemy ORM Base。"""
+

server/app/db/session.py

@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+
+from app.core.config import get_settings
+
+
+def create_engine():
+    """
+    创建异步 Engine。
+
+    注意：连接串从环境变量 `DATABASE_URL` 读取。
+    """
+
+    settings = get_settings()
+    return create_async_engine(settings.database_url, pool_pre_ping=True)
+
+
+engine = create_engine()
+
+AsyncSessionLocal: async_sessionmaker[AsyncSession] = async_sessionmaker(
+    bind=engine,
+    expire_on_commit=False,
+    autoflush=False,
+    autocommit=False,
+)
+
+
+async def get_db() -> AsyncSession:
+    """
+    FastAPI 依赖：获取数据库会话。
+    """
+
+    async with AsyncSessionLocal() as session:
+        yield session
+