ActsAsParentOf
If you are on Rails 2.3 or above, use Rails' nested attributes feature.
If you are on Rails 2.2 or below, keep reading.
This is lifted straight out of Advanced Rails Recipe 13, "Handle Multiple Models In One Form", by Ryan Bates.
For those using the recipe, you can save yourself some typing by adding the acts_as_parent_of
declaration to your parent model. For example:
class Project < ActiveRecord::Base
acts_as_parent_of :tasks, :budget
end
You'll still need to write your views and controller as explained in the recipe.
has_many versus has_one
Although the recipe assumes your parent has many children, acts_as_parent_of
also handles the case where the parent has one child (e.g. :budget
in the example above). Just remember in your controller's update
method to set the child's attributes to nil
rather than {}
. For example:
class ProjectController < ApplicationController
def update
params[:project][:existing_task_attributes] ||= {}
params[:project][:budget_attributes] ||= nil
# your normal update code etc...
end
end
Copyright (c) 2008 Andy Stewart (boss@airbladesoftware.com), released under the MIT license