Milestone 2: models associations

README.md

@@ -212,8 +212,8 @@ To execute the tests, run the following command inside the project folder:
 ## 🔭 Future Features <a name="future-features"></a>
 
 - [x] Creating a data model.
+- [x] Processing data in models.
 - [ ] Validations and Model specs.
-- [ ] Processing data in models.
 - [ ] Controllers.
 - [ ] Controllers specs.
 - [ ] Views.

app/models/comment.rb

@@ -0,0 +1,11 @@
+class Comment < ApplicationRecord
+  belongs_to :author, class_name: 'User', foreign_key: :user_id
+  belongs_to :post, class_name: 'Post', foreign_key: :post_id
+
+  # * Rails ActiveRecord callbacks to update counters in User model after saving a Comment
+  after_save :update_comments_counter
+
+  def update_comments_counter
+    post.increment!(:comments_counter)
+  end
+end

app/models/like.rb

@@ -0,0 +1,11 @@
+class Like < ApplicationRecord
+  belongs_to :author, class_name: 'User', foreign_key: :user_id
+  belongs_to :post, class_name: 'Post', foreign_key: :post_id
+
+  # * Rails ActiveRecord callbacks to update counters in User model after saving a Like
+  after_save :update_likes_counter
+
+  def update_likes_counter
+    post.increment!(:likes_counter)
+  end
+end

app/models/post.rb

@@ -0,0 +1,16 @@
+class Post < ApplicationRecord
+  belongs_to :author, class_name: 'User', foreign_key: :author_id
+  has_many :comments, class_name: 'Comment', foreign_key: :post_id, dependent: :destroy
+  has_many :likes, class_name: 'Like', foreign_key: :post_id, dependent: :destroy
+
+  # * Rails ActiveRecord callbacks to update counters in User model after saving a Post.
+  after_save :update_posts_counter
+
+  def update_posts_counter
+    author.increment!(:posts_counter)
+  end
+
+  def most_recent_comments(n_limit = 5)
+    comments.order(created_at: :desc).limit(n_limit)
+  end
+end

app/models/user.rb

@@ -0,0 +1,9 @@
+class User < ApplicationRecord
+  has_many :posts, class_name: 'Post', foreign_key: :author_id
+  has_many :comments, class_name: 'Comment', foreign_key: :user_id
+  has_many :likes, class_name: 'Like', foreign_key: :user_id
+
+  def most_recent_posts(n_limit = 3)
+    posts.order(created_at: :desc).limit(n_limit)
+  end
+end

db/migrate/20231128225500_create_posts.rb

@@ -1,7 +1,7 @@
 class CreatePosts < ActiveRecord::Migration[7.1]
   def change
     create_table :posts do |t|
-      t.references :author_id, null: false, foreign_key: { to_table: :users }
+      t.references :author, null: false, foreign_key: { to_table: :users }
       t.string :title
       t.text :text
       t.integer :comments_counter, default: 0