accessing session data

I am new to ROR and I am trying to retrieve data based on a session value I store. This is a basic app that collects user data and puts it in the DB. I then store the last insert id to a session variable on the server. This much works. The problem I am having is if that user comes back to the site I dont want to show them another form I want to show them the data they entered and I want to access the data in the DB via the ID I store. I have played with a bunch of different things but no go. Anyone have any ideas?

I get the error : You have a nil object when you didn't expect it! The error occurred while evaluating nil.order_number

I am trying to do this in my controller (the else condition works fine)

def show

if session[:id]    @something = SOMETHING.find(session[:id]) else    @something = SOMETHING.find(params[:id]) end


My show.rhtml is simply :

<% for column in SOMETHING.content_columns %> <p>   <b><%= column.human_name %>:</b> <%=h @something.send( %> </p> <% end %>