gistfile1.rb

# typical route

get '/my_model' do

  # return query results if search param, otherwise return all

  if params[:relation_id]
    MyModel.all(:relation_id => params[:relation_id], :order => :name.asc)
  else
    MyModel.all(:order => :name.asc)
  end
end

# proposed change

get '/my_model' do
  # a nil param returns all instead of all models with param set to nil
  MyModel.all(:relation_id.nilcon => params[:relation_id], :order => :name.asc)
end