Nested attributes in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to allow nested attributes for comments in the Post model.

Ruby on Rails

class Post < ApplicationRecord
  has_many :comments
  accepts_nested_attributes_for :[1]
end

Drag options to blanks, or click blank then click option'

Aposts

Bcomments

Cusers

Dauthors

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong association name in accepts_nested_attributes_for.

Forgetting to add accepts_nested_attributes_for altogether.

The method accepts_nested_attributes_for is used to allow nested attributes for associated models. Here, it should be used with :comments to enable nested attributes for comments in the Post model.

2fill in blank

medium

Complete the form helper to build fields for nested comments inside the post form.

Ruby on Rails

<%= form_with model: @post do |f| %>
  <%= f.text_field :title %>
  <%= f.fields_for :[1] do |c| %>
    <%= c.text_area :content %>
  <% end %>
<% end %>

Drag options to blanks, or click blank then click option'

Acomments

Bauthors

Cposts

Dusers

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong symbol in fields_for causing no nested fields to appear.

Not matching the association name exactly.

fields_for is used to create form fields for nested attributes. It should match the association name, which is :comments in this case.

3fill in blank

hard

Fix the error in the controller to permit nested comment attributes.

Ruby on Rails

def post_params
  params.require(:post).permit(:title, comments_attributes: [:id, :content, :[1]])
end

Drag options to blanks, or click blank then click option'

Aauthor_id

Buser_id

C_destroy

Dpost_id

Attempts:

3 left

💡 Hint

Common Mistakes

Not permitting :_destroy causes nested record deletion to fail.

Permitting unrelated keys that do not affect nested attributes.

The :_destroy key is used to allow deletion of nested records through nested attributes. It must be permitted in strong parameters to work.

4fill in blank

hard

Fill both blanks to build a nested attributes hash for a new comment with content and mark it for destruction.

Ruby on Rails

post_attributes = {
  title: 'New Post',
  comments_attributes: {
    '0' => { content: [1], [2]: true }
  }
}

Drag options to blanks, or click blank then click option'

A'Great post!'

Bcontent

C_destroy

Ddestroy

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong key name instead of :_destroy.

Putting a non-string value for content.

The content key should have a string value for the comment text. The special key :_destroy with value true marks the nested comment for deletion.

5fill in blank

hard

Fill all three blanks to create a nested attributes hash for updating a comment's content and allowing its destruction.

Ruby on Rails

post_params = {
  post: {
    title: 'Updated Post',
    comments_attributes: {
      '0' => { id: [1], content: [2], [3]: true }
    }
  }
}

Drag options to blanks, or click blank then click option'

A42

B'Updated comment content'

C_destroy

Dcontent

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string instead of a number for id.

Forgetting to include :_destroy to allow deletion.

The id should be the comment's id (number). The content is a string with the new comment text. The :_destroy key with true allows marking the comment for deletion.