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Active Record is still Magical Neeraj Singh Saturday, October 12, 13

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$ bundle exec rake test_sqlite3 3684 runs, 10491 assertions, 0 failures, 0 errors, 29 skips Saturday, October 12, 13

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# make sure we get the gem, not stdlib gem 'minitest' require 'minitest' # active_support/test_case.rb Saturday, October 12, 13

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# Returns all instance methods starting with "test_". # Based on test_order, the methods are either sorted, # randomized(default), or run in parallel. def self.runnable_methods methods = methods_matching(/^test_/) case self.test_order when :parallel max = methods.size ParallelEach.new methods.sort.sort_by { rand max } when :random then max = methods.size methods.sort.sort_by { rand max } when :alpha, :sorted then methods.sort else raise "Unknown test_order: #{self.test_order.inspect}" end end Saturday, October 12, 13

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# Defines the order to run tests # (:random by default). Override # this or use a convenience method to change it # for your tests. def self.test_order :random end Saturday, October 12, 13

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module Minitest # :nodoc: def self.__run reporter, options # :nodoc: # FIXME: MT5's runnables is not ordered. This is # needed because # we have have tests have cross-class order- dependent bugs. suites = Runnable.runnables.sort_by { |ts| ts.name.to_s } parallel, serial = suites.partition { |s| s.test_order == :parallel } ParallelEach.new(parallel).map { |suite| suite.run reporter, options } + serial.map { |suite| suite.run reporter, options } end end # active_support/test_case.rb Saturday, October 12, 13

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# FIXME: MT5's runnables is not ordered. # This is needed because # we have have tests have cross-class # order-dependent bugs. suites = Runnable.runnables.sort_by { |ts| ts.name.to_s } Saturday, October 12, 13

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module Minitest # :nodoc: def self.__run reporter, options # :nodoc: # FIXME: MT5's runnables is not ordered. This is # needed because # we have have tests have cross-class order- dependent bugs. suites = Runnable.runnables.sort_by { |ts| ts.name.to_s } suites.each { |s| puts s } parallel, serial = suites.partition { |s| s.test_order == :parallel } ParallelEach.new(parallel).map { |suite| suite.run reporter, options } + serial.map { |suite| suite.run reporter, options } end end Saturday, October 12, 13

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CalculationsTest CallbacksOnMultipleActionsTest CallbacksTest CascadedEagerLoadingTest CheckEscapedYamlFixturesTest CheckSetTableNameFixturesTest CopyMigrationsTest CopyTableTest CoreTest CounterCacheTest CustomConnectionFixturesTest CustomNameForFixtureOrModelTest DatabaseConnectedJsonEncodingTest DatabaseConnectedXmlSerializationTest DatabaseStatementsTest DateTimeTest DefaultScopingTest DefaultStringsTest Saturday, October 12, 13

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Finished in 373.451968s, 9.8647 runs/s, 28.0920 assertions/s. 3684 runs, 10491 assertions, 0 failures, 0 errors, 29 skips Saturday, October 12, 13

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Runnable.runnables.sort_by { |t| t.name.to_s } Saturday, October 12, 13

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Runnable.runnables.sort_by { |t| t.name.to_s } Runnable.runnables.sort_by { |t| t.name.to_s.reverse } Saturday, October 12, 13

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3684 runs, 10446 assertions, 8 failures, 5 errors, 29 skips sqlite3 Saturday, October 12, 13

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3924 runs, 11064 assertions, 25 failures, 41 errors, 22 skips postgresql Saturday, October 12, 13

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3684 runs, 10534 assertions, 8 failures, 4 errors, 23 skips mysql2 Saturday, October 12, 13

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Help Active Record Saturday, October 12, 13

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“Any sufficiently advanced technology is indistinguishable from magic.” ― Arthur C. Clarke, Saturday, October 12, 13

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irb(main):> User.where id: '45' SELECT "users".* FROM "users" WHERE "users"."id" = 45 Saturday, October 12, 13

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irb(main):> User.where id: '45' SELECT "users".* FROM "users" WHERE "users"."id" = 45 irb(main):> User.where name: 10 SELECT "users".* FROM "users" WHERE "users"."name" = 10 Saturday, October 12, 13

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class Physician < ActiveRecord::Base has_many :appointments has_many :patients, through: :appointments end Saturday, October 12, 13

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class Physician < ActiveRecord::Base has_many :appointments has_many :patients, through: :appointments end irb(main):> physician.appointments.create! INSERT INTO "appointments" ("physician_id") VALUES ($1) RETURNING "id" [["physician_id", 1]] => # Saturday, October 12, 13

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class Physician < ActiveRecord::Base has_many :appointments has_many :patients, through: :appointments end Saturday, October 12, 13

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class Physician < ActiveRecord::Base has_many :appointments has_many :patients, through: :appointments end irb(main):> physician.patients.create! INSERT INTO "patients" DEFAULT VALUES RETURNING "id" INSERT INTO "appointments" ("patient_id", "physician_id") VALUES ($1, $2) RETURNING "id" [["patient_id", 2], ["physician_id", 1]] => # Saturday, October 12, 13

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class Physician < ActiveRecord::Base has_many :appointments has_many :patients, through: :appointments end Saturday, October 12, 13

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class Physician < ActiveRecord::Base has_many :appointments has_many :patients, through: :appointments end irb(main):> physician.patients.where(id: 50).create! INSERT INTO "patients" ("id") VALUES ($1) RETURNING "id" [["id", 50]] => # Saturday, October 12, 13

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irb(main):> physician.patients.where(id: 50).class.name => "ActiveRecord::AssociationRelation" Saturday, October 12, 13

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irb(main):> physician.patients.class.name => "ActiveRecord::Associations::CollectionProxy" irb(main):> physician.patients.where(id: 50).class.name => "ActiveRecord::AssociationRelation" Saturday, October 12, 13

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irb(main):> Physician.all.class.name => "ActiveRecord::Relation" Saturday, October 12, 13

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irb(main):> Physician.all .where(id: 2) .where(name: 'John') .class.name => "ActiveRecord::Relation" irb(main):> Physician.all.class.name => "ActiveRecord::Relation" Saturday, October 12, 13

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class CollectionProxy < Relation end Saturday, October 12, 13

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A collectionProxy has reference to the association it is acting on class CollectionProxy < Relation end Saturday, October 12, 13

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A collectionProxy has reference to the association it is acting on class CollectionProxy < Relation end irb(main):> Physician.last .patients .instance_variable_get(:@association) .class => ActiveRecord::Associations::HasManyThroughAssociation Saturday, October 12, 13

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irb(main):> physician.patients.where(id: 50).create! INSERT INTO "patients" ("id") VALUES ($1) RETURNING "id" [["id", 50]] => # Saturday, October 12, 13

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def create(*args, &block) scoping { @klass.create(*args, &block) } end irb(main):> physician.patients.where(id: 50).create! INSERT INTO "patients" ("id") VALUES ($1) RETURNING "id" [["id", 50]] => # Saturday, October 12, 13

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def create!(attributes = {}, &block) @association.create!(attributes, &block) end def create(*args, &block) scoping { @klass.create(*args, &block) } end irb(main):> physician.patients.where(id: 50).create! INSERT INTO "patients" ("id") VALUES ($1) RETURNING "id" [["id", 50]] => # Saturday, October 12, 13

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class Car < ActiveRecord::Base scope :good, where(:id => 1) scope :bad, where(:id => 2) end Saturday, October 12, 13

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class Car < ActiveRecord::Base scope :good, where(:id => 1) scope :bad, where(:id => 2) end # using scopes Car.good.bad SELECT "cars".* FROM "cars" WHERE "cars"."id" = 2 Saturday, October 12, 13

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class Car < ActiveRecord::Base scope :good, where(:id => 1) scope :bad, where(:id => 2) end # using scopes Car.good.bad SELECT "cars".* FROM "cars" WHERE "cars"."id" = 2 # using scopes Car.bad.good SELECT "cars".* FROM "cars" WHERE "cars"."id" = 1 Saturday, October 12, 13

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class Car < ActiveRecord::Base scope :good, where(:id => 1) scope :bad, where(:id => 2) end # using scopes Car.good.bad SELECT "cars".* FROM "cars" WHERE "cars"."id" = 2 # using wheres Car.where(:id => 1).where(:id => 2) SELECT "cars".* FROM "cars" WHERE "cars"."id" = 1 AND "cars"."id" = 2 # using scopes Car.bad.good SELECT "cars".* FROM "cars" WHERE "cars"."id" = 1 Saturday, October 12, 13

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class User < ActiveRecord::Base end Saturday, October 12, 13

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class User < ActiveRecord::Base end irb(main):> User.where(name: 'john') .order('id desc') .except(:order) => SELECT "users".* FROM "users" WHERE "users"."name" = 'john' Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } end Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } end irb(main):> User.where(name: 'john') .order('id desc') .except(:order) => SELECT "users".* FROM "users" WHERE "users"."active" = 't' AND "users"."name" = 'john' Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } end irb(main):> User.where(name: 'john') .order('id desc') .except(:order) => SELECT "users".* FROM "users" WHERE "users"."active" = 't' AND "users"."name" = 'john' irb(main):> User.order('id desc') .except(:where) => SELECT "users".* FROM "users" ORDER BY id desc Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { except(:where) .where(created_at: Time.now.all_year) } end Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { except(:where) .where(created_at: Time.now.all_year) } end irb(main):> User.signed_in_2013 => SELECT "users".* FROM "users" WHERE "users"."active" = 't' AND ("users"."created_at" BETWEEN '2013-01-01 05:00:00.000000' AND '2014-01-01 04:59:59.999999') Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { except(:where) .where(created_at: Time.now.all_year) } end irb(main):> User.signed_in_2013 => SELECT "users".* FROM "users" WHERE "users"."active" = 't' AND ("users"."created_at" BETWEEN '2013-01-01 05:00:00.000000' AND '2014-01-01 04:59:59.999999') In Rails 4.0.0 default_scope is applied lazily at the very end of the relation. rails 4.0.0 Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { except(:where) .where(created_at: Time.now.all_year) } end Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { except(:where) .where(created_at: Time.now.all_year) } end irb(main):> User.signed_in_2013 => SELECT "users".* FROM "users" AND ("users"."created_at" BETWEEN '2013-01-01 05:00:00.000000' AND '2014-01-01 04:59:59.999999') rails edge Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { unscoped.where(created_at: Time.now.all_year) } end Saturday, October 12, 13

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class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { unscoped.where(created_at: Time.now.all_year) } end class User < ActiveRecord::Base default_scope { where(active: true) } scope :signed_in_2013, -> { build_default_scope.except(:where). where(created_at: Time.now.all_year) } end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end irb(main):> User.preload(:posts).to_a User Load (0.7ms) SELECT "users".* FROM "users" SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1) Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end irb(main):> User.preload(:posts).to_a User Load (0.7ms) SELECT "users".* FROM "users" SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1) - preload loads the association data in separate queries - this is how include works in default case Saturday, October 12, 13

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irb(main):> User.preload(:posts) .where("posts.desc='ruby is awesome'") => PG::Error: ERROR: missing FROM-clause entry for table "posts" Saturday, October 12, 13

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irb(main):> User.preload(:posts) .where("posts.desc='ruby is awesome'") => PG::Error: ERROR: missing FROM-clause entry for table "posts" irb(main):> User.preload(:posts) .where("users.name='John'") => SELECT "users".* FROM "users" WHERE (users.name='John') Saturday, October 12, 13

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irb(main):> User.eager_load(:posts) SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, "users"."email" AS t0_r2, "users"."active" AS t0_r3, "users"."created_at" AS t0_r4, "users"."updated_at" AS t0_r5, "posts"."id" AS t1_r0, "posts"."name" AS t1_r1, "posts"."title" AS t1_r2, "posts"."user_id" AS t1_r3 FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id" Saturday, October 12, 13

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irb(main):> User.includes :posts SELECT "users".* FROM "users" SELECT "posts".* FROM "posts" WHERE "posts"."user_id" IN (1) Saturday, October 12, 13

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irb(main):> User.includes(:posts).references(:posts) SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, "users"."email" AS t0_r2, "users"."active" AS t0_r3, "users"."created_at" AS t0_r4, "users"."updated_at" AS t0_r5, "posts"."id" AS t1_r0, "posts"."name" AS t1_r1, "posts"."title" AS t1_r2, "posts"."user_id" AS t1_r3 FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id" Saturday, October 12, 13

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irb(main):> User.includes(:posts) .where('posts.name' => "ruby is awesome") SELECT "users"."id" AS t0_r0, "users"."name" AS t0_r1, "users"."email" AS t0_r2, "users"."active" AS t0_r3, "users"."created_at" AS t0_r4, "users"."updated_at" AS t0_r5, "posts"."id" AS t1_r0, "posts"."name" AS t1_r1, "posts"."title" AS t1_r2, "posts"."user_id" AS t1_r3 FROM "users" LEFT OUTER JOIN "posts" ON "posts"."user_id" = "users"."id" WHERE "posts"."name" = 'ruby is awesome' Saturday, October 12, 13

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irb(main):> User.joins(:posts) SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_id" = "users"."id" Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end irb(main):> user = User.create! Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end irb(main):> user = User.create! irb(main):> user.posts.create! name: 'ruby' Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end irb(main):> user = User.create! irb(main):> user.posts.create! name: 'ruby' irb(main):> user.posts[0].name = 'rails' Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end irb(main):> user = User.create! irb(main):> user.posts.create! name: 'ruby' irb(main):> user.posts[0].name = 'rails' irb(main):> user.save DEBUG -- : (0.4ms) BEGIN DEBUG -- : (0.3ms) COMMIT => true Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end irb(main):> user = User.create! Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end irb(main):> user = User.create! irb(main):> user.posts.create! name: 'ruby' Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end irb(main):> user.posts[0].name = 'rails' irb(main):> user = User.create! irb(main):> user.posts.create! name: 'ruby' Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end irb(main):> user.posts[0].name = 'rails' irb(main):> user.save UPDATE "posts" SET "name" = $1 WHERE "posts"."id" = 5 [["name", "rails"]] irb(main):> user = User.create! irb(main):> user.posts.create! name: 'ruby' Saturday, October 12, 13

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class Post < ActiveRecord::Base belongs_to :user, autosave: true end Saturday, October 12, 13

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irb(main):> post.user.name = 'John' class Post < ActiveRecord::Base belongs_to :user, autosave: true end Saturday, October 12, 13

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irb(main):> post.user.name = 'John' class Post < ActiveRecord::Base belongs_to :user, autosave: true end irb(main):> post.save UPDATE "users" SET "name" = $1, "updated_at" = $2 WHERE "users"."id" = 4 [["name", "John"], ["updated_at", Thu, 10 Oct 2013 03:35:01 UTC +00:00]] Saturday, October 12, 13

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class Post < ActiveRecord::Base belongs_to :user, autosave: true before_save :add_salutation def add_salutation self.user.name = 'Hello ' + self.user.name end end Saturday, October 12, 13

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class Post < ActiveRecord::Base belongs_to :user, autosave: true before_save :add_salutation def add_salutation self.user.name = 'Hello ' + self.user.name end end class Post < ActiveRecord::Base # before_belongs_to definition before_save :add_salutation belongs_to :user, autosave: true def add_salutation self.user.name = 'Hello ' + self.user.name end end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' irb(main):> post.name = nil => nil Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' irb(main):> post.name = nil => nil irb(main):028:0> post.valid? => false Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' irb(main):> post.name = nil => nil irb(main):028:0> post.valid? => false irb(main):029:0> user.valid? => true Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' irb(main):> post.name = nil => nil Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' irb(main):> post.name = nil => nil irb(main):028:0> post.valid? => false Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts, autosave: true end class Post < ActiveRecord::Base belongs_to :user validates :name, presence: true end irb(main):> post = user.posts.create name: 'rails' irb(main):> post.name = nil => nil irb(main):028:0> post.valid? => false irb(main):029:0> user.valid? => false Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user end Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user end irb(main):> user.object_id => 70196526096800 irb(main):> user.posts.first.user.object_id SELECT "posts".* FROM "posts" WHERE .......... SELECT "users".* FROM "users" WHERE .......... => 70196526747120 Saturday, October 12, 13

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class User < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :user end irb(main):> user.object_id => 70196526096800 irb(main):> user.posts.first.user.object_id SELECT "posts".* FROM "posts" WHERE .......... SELECT "users".* FROM "users" WHERE .......... => 70196526747120 rails 4.0.0 Saturday, October 12, 13

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irb(main):> user.object_id => 70196526096800 irb(main):> user.posts.first.user.object_id SELECT "posts".* FROM "posts" WHERE .......... SELECT "users".* FROM "users" WHERE .......... => 70196526747120 Saturday, October 12, 13

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irb(main):> user.object_id => 70196526096800 irb(main):> user.posts.first.user.object_id SELECT "posts".* FROM "posts" WHERE .......... SELECT "users".* FROM "users" WHERE .......... => 70196526747120 rails 4.0.0 Saturday, October 12, 13

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irb(main):> user.object_id => 70196526096800 irb(main):> user.posts.first.user.object_id SELECT "posts".* FROM "posts" WHERE .......... SELECT "users".* FROM "users" WHERE .......... => 70196526747120 rails 4.0.0 irb(main):> user.object_id => 70196526096800 irb(main):> user.posts.first.user.object_id SELECT "posts".* FROM "posts" WHERE .......... => 70196526096800 rails edge Saturday, October 12, 13

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inverse_of is auto derived in rails 4.1 Saturday, October 12, 13

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inverse_of is auto derived in rails 4.1 rails edge Saturday, October 12, 13

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If you do not set the :inverse_of record, the association will do its best to match itself up with the correct inverse. Saturday, October 12, 13

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If you do not set the :inverse_of record, the association will do its best to match itself up with the correct inverse. rails edge Saturday, October 12, 13

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However, associations that contain the following options will not have their inverses set automatically :conditions :through :polymorphic :foreign_key Saturday, October 12, 13

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However, associations that contain the following options will not have their inverses set automatically :conditions :through :polymorphic :foreign_key rails edge Saturday, October 12, 13

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class User < ActiveRecord::Base end User.new.save Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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# module Persistence def save(*) create_or_update rescue ActiveRecord::RecordInvalid false end Saturday, October 12, 13

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# module Persistence def save(*) create_or_update rescue ActiveRecord::RecordInvalid false end def create_or_update raise ReadOnlyRecord if readonly? result = new_record? ? create_record : update_record result != false end Saturday, October 12, 13

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# module Validations def save(options={}) perform_validations(options) ? super : false end Saturday, October 12, 13

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# module AttributeMethods def save(*) if status = super @previously_changed = changes @changed_attributes.clear end status end Saturday, October 12, 13

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# module Transactions def save(*) #:nodoc: rollback_active_record_state! do with_transaction_returning_status { super } end end def rollback_active_record_state! remember_transaction_record_state yield rescue Exception restore_transaction_record_state raise ensure clear_transaction_record_state end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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module ActiveRecord class Base ...................... include Persistence ....................... include Validations ........................ include AttributeMethods ........................ include Transactions ........................ end end Saturday, October 12, 13

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entering save in transactions entering save in attribute_methods entering save in validations entering save in persistence leaving save in persistence leaving save in validations leaving save in attribute_methods leaving save in transactions Life cycle of save in Active Record Saturday, October 12, 13

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Saturday, October 12, 13

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class Comment < ActiveRecord::Base belongs_to :post end class Author < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :author has_many :comments end Comment.joins(:post) .merge(Post.joins(:author) .merge(Author.where(:name => "Joe"))).all Saturday, October 12, 13

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class Comment < ActiveRecord::Base belongs_to :post end class Author < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :author has_many :comments end Comment.joins(:post) .merge(Post.joins(:author) .merge(Author.where(:name => "Joe"))).all Association named 'author' was not found on Comment Saturday, October 12, 13

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class Comment < ActiveRecord::Base belongs_to :post end class Author < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :author has_many :comments end Comment.joins(:post) .merge(Post.joins(:author) .merge(Author.where(:name => "Joe"))).all Association named 'author' was not found on Comment rails 3.2.x Saturday, October 12, 13

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irb(main):> Post.joins(:author).merge( Author.where(:name => "J")).joins_values => [:author] irb(main):> Post.joins(:author).merge( Author.where(:name => "J")).where_values => [#, name="name">, @right="Joe">] Saturday, October 12, 13

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j = Comment.joins(:post).merge( Post.joins(:author).merge( Author.where(:name => "Joe"))).joins_values Saturday, October 12, 13

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irb(main):> j.first => :post irb(main):> j.second => [] irb(main):> j.third.class.name "ActiveRecord::Associations::JoinDependency::JoinAsso ciation" irb(main):> j.third.reflection.class.name => "ActiveRecord::Reflection::AssociationReflection" irb(main):> j.third.tables => [#] Saturday, October 12, 13

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irb(main):> j.first => :post rails 4.0.0 irb(main):> j.second => [] irb(main):> j.third.class.name "ActiveRecord::Associations::JoinDependency::JoinAsso ciation" irb(main):> j.third.reflection.class.name => "ActiveRecord::Reflection::AssociationReflection" irb(main):> j.third.tables => [#] Saturday, October 12, 13

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class Comment < ActiveRecord::Base belongs_to :post end class Author < ActiveRecord::Base has_many :posts end class Post < ActiveRecord::Base belongs_to :author has_many :comments end Comment.joins(:post) .merge(Post.joins(:author) .merge(Author.where(:name => "Joe"))).all Saturday, October 12, 13

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Neeraj Singh @neerajdotname @BigBinary Saturday, October 12, 13