Associations

Associations

Generate basic CRUD for authors

rails g scaffold Author name:string email:string --no-helper --no-assets

Generate association between articles and authors

rails g migration AddAuthorToArticles author:references

nano app/models/article.rb

class Article < ActiveRecord::Base
  belongs_to :author
  ..

nano app/models/author.rb

class Author < ActiveRecord::Base
  has_many :articles
  ...

rake db:migrate

Add author_id to trusted parameters

nano app/controllers/articles_controller.rb

...
    def article_params
      params.require(:article).permit(:title, :content, :author_id)
    end
...

Create author using cURL

curl -H "Accept: application/json" \
     http://localhost:3000/authors \
     --data "author[name]=Author Name" \
     --data "author[email]=author@domain.local"

Open author in the browser and check if the new record was created

open http://localhost:3000/authors

Associate author to existing article using cURL

curl -H "Accept: application/json" \
     http://localhost:3000/articles/1.json \
     --data "_method=patch" \
     --data "article[author_id]=1"

Add author to articles views HTML

nano app/views/articles/index.html.erb

...
      <th>Title</th>
      <th>Content</th>
      <th>Author</th>
...
        <td><%= article.title %></td>
        <td><%= article.content %></td>
        <td><%= article.author.name if article.author %></td>
...

nano app/views/articles/_form.html.erb

...
  <div class="field">
    <%= f.label :author %><br>
    <%= f.collection_select(:author_id, Author.all, :id, :name, prompt: 'Select Author') %>
  </div>
...

nano app/views/articles/show.html.erb

...
<p>
  <strong>Author:</strong>
  <%= @article.author.name if @article.author %>
</p>
...

Add author to articles views JSON

nano app/views/articles/index.json.jbuilder

json.extract! article, :id, :title, :content, :author

nano app/views/articles/show.json.jbuilder

json.extract! @article, :id, :title, :content, :author, :created_at, :updated_at

Open articles in the browser and check if there are records with authors

open http://localhost:3000/articles

Add authors and associations to Git

git add .
git commit -m "Add authors and associations"

Next step: SimpleForm