title: "error(s) on assignment of multiparameter attributes" date/time fields
body: <p>My application has a model "Appointments" which have a start and end attribute both which are datetimes. I am trying to set the date and time parts separately from my form so I can use a separate date and time picker. I thought I should be able to do it like this. From what I ahve read rails should combine the two parts and then parse the combined field as a datetime like it usually would
  The error I am getting:</p>
  
  <pre><code>2 error(s) on assignment of multiparameter attributes [error on assignment ["2013-09-16", "15:30"] to start (Missing Parameter - start(3)),error on assignment ["2013-09-16", "16:30"] to end (Missing Parameter - end(3))]
  </code></pre>
  
  <p>These are the request parameters:</p>
  
  <pre><code>{"utf8"=&gt;"✓", "authenticity_token"=&gt;"OtFaIqpHQFnnphmBmDAcannq5Q9GizwqvvwyJffG6Nk=", "appointment"=&gt;{"patient_id"=&gt;"1", "provider_id"=&gt;"1", "start(1s)"=&gt;"2013-09-16", "start(2s)"=&gt;"15:30", "end(1s)"=&gt;"2013-09-16", "end(2s)"=&gt;"16:30", "status"=&gt;"Confirmed"}, "commit"=&gt;"Create Appointment", "action"=&gt;"create", "controller"=&gt;"appointments"}
  </code></pre>
  
  <p>My Model</p>
  
  <pre><code>class Appointment &lt; ActiveRecord::Base
      belongs_to :patient
      belongs_to :practice
      belongs_to :provider
    validates_associated :patient, :practice, :provider
  
  
  end
  </code></pre>
  
  <p>And the relevant part of the view: (its a simple form)</p>
  
  <pre><code>      &lt;%= f.input :"start(1s)", :as =&gt; :string, :input_html =&gt; { :class =&gt; 'date_time_picker' , :value =&gt; Date.parse(params[:start]) }%&gt;
        &lt;%= f.input :"start(2s)", :as =&gt; :string, :input_html =&gt; { :class =&gt; 'date_time_picker' , :value =&gt; Time.parse(params[:start]).strftime('%R') }%&gt;
  
        &lt;%= f.input :"end(1s)", :as =&gt; :string, :input_html =&gt; { :class =&gt; 'date_time_picker' , :value =&gt; Date.parse(params[:end]) }%&gt;
        &lt;%= f.input :"end(2s)", :as =&gt; :string, :input_html =&gt; { :class =&gt; 'date_time_picker' , :value =&gt; Time.parse(params[:end]).strftime('%R') }%&gt;
  </code></pre>
  
  <p>UPDATE:
  THis is now how my model looks like, Ive been trying to do getter/setter methods but I am stuck because start-dat, start_time etc are nil in the model and the parameters aren't sent through</p>
  
  <pre><code>class Appointment &lt; ActiveRecord::Base
      belongs_to :patient
      belongs_to :practice
      belongs_to :provider
      validates_associated :patient, :practice, :provider
      before_validation :make_start, :make_end
  
  
      ############ Getter Methods for start/end date/time
      def start_time
          return start.strftime("%X") if start
      end
  
      def end_time
          return self.end.strftime("%X") if self.end
      end
  
      def start_date
          return start.strftime("%x") if start
      end
  
      def end_date
          return self.end.strftime("%x") if self.end
      end
  
  
      def start_time=(time)
      end
  
      def end_time=(time)
      end
  
      def start_date=(date)
      end
  
      def end_date=(date)
      end
  
  
      def make_start
          if defined?(start_date)
              self.start = DateTime.parse( self.start_date + " " + self.start_time)
          end
      end
  
      def make_end
          if defined?(end_date)
              self.start = DateTime.parse( end_date + " " + end_time)
          end
      end
  end
  </code></pre>