如何在codeigniter中保存和提取会话数据

I save some data in session on my verify controller then I extract this session data into user_activity model and insert session data into activity table. My problem is only username data saved in session and I can get and insert only username data after extracting session on model. I am new in Codeigniter. For this reason It’s very difficult to find out the problem. I am trying several days finding the problem. But unfortunately I can’t. So please, anyone help me. ThanksI save some data in session on my verify contro