Ruby-on-rails – Create a new child in the Parent program

# routes.rb
resources :parents do
 member do
 post'create_child'
 end
end

# parents/show .html.erb
<%= form_for @child, :url => create_child_parent_path(@parent) do |f| %>
...
<% end %>

# parents_controller.rb
def create_child
 @parent = Parent.find(params[:id] )
 @child = @parent.children.build(params[:child])
 if @child.save
 @child = Child.new
 end
 render :action => :show
end

In the show view of the existing Parent, I want to have a form to create Children.

I have figured out how to create A Child form and include it in the Parent’s program instead of how to exclude the parent_id field. How to assign parent_id to the child without using the form field?

I think the best way to deal with this problem is to use the member routing of the parent controller so that when you create a child, you always know what it belongs to through the routing Parent. For example:

# routes.rb
resources :parents do
 member do
 post'create_child'
 end
end

And then in your opinion

# parents/show.html.erb
<%= form_for @child, :url => create_child_parent_path(@parent) do |f| %>
...
<% end %>

Finally in your controller

# parents_controller.rb
def create_child
 @parent = Parent.find(params[:id])
 @child = @parent.children .build(params[:child])
 if @child.save
 @child = Child.new
 end
 render :action => :show
end< /pre> 

The key here is that even if the form does not contain information about the parent, when you use the build method on the association, the parent_id is assigned by default.

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