title: How to update table row from values determined within controller
body: <p>ruby_on_rails rails 4 assignment non-screen data to insert record</p>
  
  <p>Rather than using screen values (e.g. simple_form_for @user_evaluation_result) to populate the columns to insert a row I need to calculate some of the values in controller.
  For example if I have these statements in the controller</p>
  
  <pre><code>….
  # which if I had simple_form_for user_evaluation_result would get populated by the screen 
  @user_evaluation_result = UserEvaluationResult.new(user_evaluation_result_params)
  ….
  # standard stuff I use for screen derived updates
  def user_evaluation_result_params
      params.require(:user_evaluation_result).
          permit(:evaluation_assumption_id,
                 :company_listing_id,
                 :target_share_price_dollars )
    end
  </code></pre>
  
  <p>How do I assign values to :user_assumption_id etc so that insert works.  I have tried all sorts of statements.  Alternatively do I use another format instead of calling "def user_evaluation_result_params".
  Thanks in advance - Pierre</p>