diff --git a/server/db/models/message_model.py b/server/db/models/message_model.py
index 9299e98..7b76df1 100644
--- a/server/db/models/message_model.py
+++ b/server/db/models/message_model.py
@@ -9,7 +9,7 @@ class MessageModel(Base):
     """
     __tablename__ = 'message'
     id = Column(String(32), primary_key=True, comment='聊天记录ID')
-    conversation_id = Column(String(32), index=True, comment='对话框ID')
+    conversation_id = Column(String(32), default=None, index=True, comment='对话框ID')
     # chat/agent_chat等
     chat_type = Column(String(50), comment='聊天类型')
     query = Column(String(4096), comment='用户问题')