{"id":1131,"date":"2015-08-05T03:23:10","date_gmt":"2015-08-05T03:23:10","guid":{"rendered":"http:\/\/www.honobono-life.info\/wpeng\/?p=1131"},"modified":"2015-08-05T03:23:10","modified_gmt":"2015-08-05T03:23:10","slug":"micropost-modelassociations","status":"publish","type":"post","link":"http:\/\/www.honobono-life.info\/wpeng\/micropost-modelassociations\/","title":{"rendered":"Ruby on Rails Tutorial micropost model,associations"},"content":{"rendered":"

(1)micropost model<\/strong><\/p>\r\n\r\n

1.basic model<\/strong><\/p>\r\n\r\n

$ rails generate model Micropost content:string user_id:integer<\/p>\r\n\r\n

2.add index<\/strong><\/p>\r\n\r\n

$ vi db\/migrate\/…._create_microposts.rb<\/p>\r\n\r\n

\r\nclass CreateMicroposts < ActiveRecord::Migration\r\n  def change\r\n    create_table :microposts do |t|\r\n      t.string :content\r\n      t.integer :user_id\r\n\r\n      t.timestamps\r\n    end\r\n    add_index :microposts, [:user_id, :created_at]\r\n  end\r\nend<\/pre>\r\n\r\n
3.migrate<\/strong><\/p>\r\n\r\n
$ bundle exec rake db:migrate<\/p>\r\n\r\n
4.micropost validations<\/p>\r\n\r\n
$ vi app\/models\/micropost.rb<\/p>\r\n\r\n
\r\nclass Micropost < ActiveRecord::Base\r\n  validates :content, presence: true, length: { maximum: 140 }\r\n  validates :user_id, presence: true\r\nend<\/pre>\r\n\r\n
(2)User\/Micropost associations<\/strong><\/p>\r\n\r\n
1. Micropost model<\/strong><\/p>\r\n\r\n
$ vi app\/models\/micropost.rb<\/p>\r\n\r\n
\r\nclass Micropost < ActiveRecord::Base\r\n  belongs_to :user\r\n......<\/pre>\r\n\r\n
2. User model<\/strong><\/p>\r\n\r\n
$ vi app\/models\/user.rb<\/p>\r\n\r\n
\r\nclass User < ActiveRecord::Base\r\n  has_many :microposts, dependent: :destroy\r\n.....<\/pre>\r\n\r\n
3. check<\/strong><\/p>\r\n\r\n
$ rails console<\/p>\r\n\r\n
2.0.0p247 :001 > micropost = Micropost.create(content: "Test #1", user_id: 10)<\/p>\r\n\r\n
2.0.0p247 :002 > micropost = Micropost.create(content: "Test #2", user_id: 10)<\/p>\r\n\r\n
2.0.0p247 :003 > micropost=Micropost.find_by(user_id: 10)
\r\n  Micropost Load (0.3ms)  SELECT  "microposts".* FROM "microposts"  WHERE "microposts"."user_id" = 10 LIMIT 1
\r\n => #<Micropost id: 1, content: "Test #1", user_id: 10, created_at: "2015-07-21 00:00:50", updated_at: "2015-07-21 00:00:50"><\/p>\r\n\r\n
2.0.0p247 :004 > micropost.user
\r\n  User Load (0.1ms)  SELECT  "users".* FROM "users"  WHERE "users"."id" = ? LIMIT 1  [["id", 10]]
\r\n => #<User id: 10, name: "testuser10", email: "test10@example.com", created_at: "2015-07-13 08:45:35", updated_at: "2015-07-20 08:30:47", password_digest: "$2a$10$BLM\/nUrE1wptItRDOkKm4OynNZ718yjoDnnIBUkWL0s…", remember_token: "48c3edd244e42156c38e89fca5fe5616c5cfcce1", admin: false><\/p>\r\n","protected":false},"excerpt":{"rendered":"
(1)micropost model 1.basic model $ rails generate model Micropost content:string user_id:integer 2.add index $ vi db\/migrate\/…._create_microposts.rb class CreateMicroposts < ActiveRecord::Migration def change create_table :microposts do |t| t.string :content t.integer :user_id t.timestamps end add_index :microposts, [:user_id, :created_at] end end 3.migrate $ bundle exec rake db:migrate 4.micropost validations $ vi app\/models\/micropost.rb class Micropost < ActiveRecord::Base validates :content, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[137],"tags":[180,178,179],"amp_enabled":true,"_links":{"self":[{"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/posts\/1131"}],"collection":[{"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/comments?post=1131"}],"version-history":[{"count":1,"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/posts\/1131\/revisions"}],"predecessor-version":[{"id":1132,"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/posts\/1131\/revisions\/1132"}],"wp:attachment":[{"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/media?parent=1131"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/categories?post=1131"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.honobono-life.info\/wpeng\/wp-json\/wp\/v2\/tags?post=1131"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}