store session variable in a table

hi,can anyone tell me how a session variable can store in table,

Do you mean change from storing sessions in a cookie to storing in
your database?
Or do you mean something to do with using the session?

no, suppose that there’s a person who has logged in to a site

and when he fill a form so the data should be stored in a table

with his user id which has stored in his session. so how can

i store it.

You could access the session in the controller at the time the user
Depends on what your authentication system does.
For instance it might be session[:user]. So you have to do something
to verify the user id is valid.
There may be helper methods which come with whatever plugin or system
you're using
so you should check them out.

If you don't have a system, there are quite a few.
acts_as_authenticated, restful_authentication to name 2.
You'll need to install one of them and read how to use it.

thank you very much,now i can understand what should i do