## controller

 def create
    @state = State.new(params[:state])
    @state.tags.each {|tag| tag.destroy}
    @state.tags = params[:tags].map {|tag| Tag.find_by_id tag}

    respond_to do |format|
      if @state.save
        flash[:notice] = 'State was successfully created.'
        format.html { redirect_to(@state) }
        format.xml  { render :xml => @state, :status => :created, :location => @state }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @state.errors, :status => :unprocessable_entity }
      end
    end
  end


## error

 ActiveRecord::StatementInvalid in StatesController#create

Mysql::Error: Duplicate entry '1' for key 'PRIMARY': INSERT INTO states_tags (`updated_at`, `tag_id`, `id`, `state_id`, `created_at`) VALUES ('2009-06-12 10:59:01', 1, 1, 18, '2009-06-12 10:59:01')

RAILS_ROOT: C:/rails/webstate