diff --git a/src/database/database.py b/src/database/database.py
index 12dbd40..fbdc4b6 100644
--- a/src/database/database.py
+++ b/src/database/database.py
@@ -67,6 +67,14 @@ class DatabaseManager:
             self.is_connected = False
             logger.info("数据库连接已断开")
     
+    async def session(self):
+        """获取数据库会话的异步上下文管理器"""
+        if not self.is_connected:
+            await self.connect()
+        
+        async with self.async_session() as session:
+            yield session
+    
     async def get_session(self) -> AsyncSession:
         """获取数据库会话"""
         if not self.is_connected:
diff --git a/src/database/init_db.py b/src/database/init_db.py
index 8e9bed8..120aa67 100644
--- a/src/database/init_db.py
+++ b/src/database/init_db.py
@@ -119,8 +119,13 @@ async def init_database():
         await db_manager.connect()
         await db_manager.create_tables()
         
-        async with db_manager.session() as session:
+        async with db_manager.get_session() as session:
             perm_map = await init_permissions(session)
+            if perm_map is None:
+                # Permissions already existed, fetch them from database
+                result = await session.execute(select(Permission))
+                perms = result.scalars().all()
+                perm_map = {perm.code: perm.id for perm in perms}
             await init_roles(session, perm_map)
             await create_admin_user(session)