storing a value before nullifying a rails association - ruby-on-rails

Question

Ok, im new to ruby and rails, I cant seem to get which I would assume to be simple working. Basically my code is to remove a reference to an association (nil it).
I want to get the name member (Team.name) of the model and save it to (team_name) before removing the association for the flash message.
Here is the controller action and Models:
def remove_resource
...
#user = User.find(params[:user_id])
team_name = #user.team.name
#user.team = nil
if #user.save
flash[:notice] = "#{#user.name} was removed from "+team_name+". They are no longer on a team."
...
end
...
end
class Team < ActiveRecord::Base
has_many :user, :class_name => "User", :foreign_key => "user_id",
:order => "team_start"
...
def ==(another_team)
if self.name != another_team.name then
return false
end
if self.location != another_team.location then
return false
end
...
true
end
...
end
class User < ActiveRecord::Base
belongs_to :team, :class_name => "Team",
:foreign_key => "team_id"
...
end
The Errors I am receiving:
NoMethodError in UsersController#remove_resource
undefined method `name' for nil:NilClass
The trace:
app/models/user.rb:50:in `=='
app/controllers/teams_controller.rb:50:in `remove_resource'
Now the error only occurs when I retrieve the
#user.team.name
If I delete this and the reference to the variable team_name, all works fine.
Thanks!

Answer 1

You get this error because you dont have the #user.team associated anymore. There is only a nil which doesnt have the Model specific method name. So you need to validate if threre is a team associated or not before executing methods of a associated object that may not be there.
def remove_resource
...
#user = User.find(params[:user_id])
if #user.team.nil? # Check if theres a associated object
#do sth. when theres no team to remove
else
team_name = #user.team.name
#user.team = nil
if #user.save
flash[:notice] = "#{#user.name} was removed from "+team_name+". They are no longer on a team."
...
end
...
end