Rails - Jan 2006 - Updating :has_many - :through related items

Hi,

I''ve got my little app working pretty well. I''m using pretty
much the
model and table layout from my previous thread, as suggested by Bill
Katz:

<http://www.ruby-forum.com/topic/52506#26260>

I have the Create page working and a delete Match page working, which
along with the appropriate record in the Matches table, removes the
linked items in the competitions table.

Now I''m working on the Update page and am not sure I''m doing
it the
best way.. not to mention it''s not working and looking at the log,
seems to make a ton of trips to the database. My Edit form includes:

<select name="Red[]" id="red1">
	<%= "<option value=""0"">Red
1</option>" if controller.action_name == ''new''
%>
<%= options_from_collection_for_select(@teams, "id",
"number",
@match_teams[0]) %>
</select>
<select name="Red[]" id="red2">
	<%= "<option value=""0"">Red
2</option>" if controller.action_name == ''new''
%>
<%=  options_from_collection_for_select(@teams, "id",
"number",
@match_teams[1]) %>
</select>
<select name="Red[]" id="red3">
	<%= "<option value=""0"">Red
3</option>" if controller.action_name == ''new''
%>
<%=  options_from_collection_for_select(@teams, "id",
"number",
@match_teams[2]) %>
</select>

(There are three more <select> tags for the "blue" side, using
@match_teams[3] through 5)

The Edit controller defines @match_teams as:

@match = Match.find(params[:id])
@teams = Team.find(:all, :order => "number")
@match_teams = []
@match.competitions.each do |team|
  @match_teams << team.team_id
end

Now in the update method I''m doing this, but it looks messy and
doesn''t seem to update the correct records:

@match = Match.find(params[:id])
if @match.update_attributes(params[:match])
  for i in 0..2
    if @match.competitions[i].team_id != params[:Red][i] then
      @match.competitions[i].team_id = params[:Red][i]
      @match.competitions[i].save
    end
  end
  for i in 3..5
    if @match.competitions[i].team_id != params[:Blue][i] then
      @match.competitions[i].team_id = params[:Blue][i]
      @match.competitions[i].save
    end
  end

Is there a better way to do what I want.. update all of the
corresponding changed items?

Thanks.

jt

On 1/30/06, John Tsombakos <johnt519@gmail.com>
wrote:
> Hi,
...

Well, I figured out why it wasn''t working. In this
bit:
>
> @match = Match.find(params[:id])
> if @match.update_attributes(params[:match])
>   for i in 0..2
>     if @match.competitions[i].team_id != params[:Red][i] then
>       @match.competitions[i].team_id = params[:Red][i]
>       @match.competitions[i].save
>     end
>   end
>   for i in 3..5
>     if @match.competitions[i].team_id != params[:Blue][i] then
>       @match.competitions[i].team_id = params[:Blue][i]
>       @match.competitions[i].save
>     end
>   end
I had to change the comparison to:
  if @match.competitions[i].team_id != params[:Red][i].to_i

to compare integers.  And the second loop, I had to change the
params[:Blue][i] to params[:Blue][i-3]

It works now, but I''d still like to know if I''m doing more
work than
necessary, or missing some "Ruby-ism" that would help.

Thanks.
jt