[RUBY] Rasils data save, update, delete
      
      
        
        
        
        
  Purpose of this post  h1>
 -Minutes about Rails controller operations ((1) save, (2) update, (3) delete).
  Teaching materials used for learning  h1>
 Udemy ["Introduction to Ruby on Rails for the First Time-Learn Ruby and Rails from the Basics and Publish Web Applications to the Net"](https://www.udemy.com/course/the-ultimate-ruby-on-rails- I used bootcamp /) as a teaching material.
  ① Save (create)  h1>
 -Reflect the newly created value in db and save it
qiita.rb
 def create
    @instance=model.new(Key 1:Value 1,Key 2:Value 2)
    @instance.save
  end
[Explanation]
○ @ Instance = Model.new (Key 1: Value 1, Key 2: Value 2)
⇨ Store the value in db via the instance variable
○ @ Instance.save
⇨ ⇨ Save instance variables
  2 update  h1>
 -Update the value already saved in db
 ・ (I want to update from value 1 → value 1_1, value 2 → value 2_2)
qiita.rb
  def update
    @instance=model.find(params[:id])
    @instance.update(Key 1:Value 1_2,Key 2:Value 2_2)
  end
[Explanation]
○ @ Instance = Model.new (params [: id])
⇨ Specify the key as an argument and store the hash value of db in the instance.
○ @ Instance.update
⇨ ⇨ Update instance variables
  ③ Delete (destroy)  h1>
 -Delete the value already saved in db
qiita.rb
  def destroy
    @instance=model.find(params[:id])
    @instance.destroy
  end
[Explanation]
○ @ Instance.destroy
⇨ Delete all db cache data
  About CRUD  h1>
 ・ How to read is clad
 ・ Generic term for Create, Read, Update, Delete
 ・ C, U, D correspond to those explained in this article.
 ・ (C = ①create, U = ②update, D = ③destroy)
 ・ For R, index action and show action are equivalent.
 ・ R does not change the value of db, so it will not be explained in detail here.