MittalPatel-BTC

# Example to destroy all users matching the given condition
  User.find_by(email: "mit@gmail.com").destroy
  User.where(email: "mit@gmail.com", rating: 4).destroy_all

# Example to delete all users matching the given condition
  User.find_by(email: "mit@gmail.com").delete
  User.where(email: "mit@gmail.com", rating: 4).delete_all

MittalPatel-BTC

# Rails 6
> User.first.update_columns(office_email: 'mit@gmail.com')

SELECT "users".* FROM "users" ORDER BY "users"."id" ASC LIMIT ?  [["LIMIT", 1]]

Traceback (most recent call last):
        1: from (irb):1
ActiveModel::MissingAttributeError (can't write unknown attribute `office_email`)

MittalPatel-BTC

# Rails 5.2
> User.first.update_columns(office_email: 'mit@gmail.com')
SELECT  "users".* FROM "users" ORDER BY "users"."id" ASC LIMIT $1  [["LIMIT", 1]]
UPDATE "users" SET "office_email" = $1 WHERE "users"."id" = $2  [["office_email", "mit@gmail.com"], ["id", 1]]

=> Traceback (most recent call last):
        1: from (irb):8
ActiveRecord::StatementInvalid (PG::UndefinedColumn: ERROR:  column "office_email" of relation "users" does not exist)
LINE 1: UPDATE "users" SET "office_email" = $1 WHERE "users"."id" = $2
                           ^

MittalPatel-BTC

# Example to destroy all users matching the given condition using destroy_by
  User.destroy_by(email: "mit@gmail.com")
  User.destroy_by(email: "mit@gmail.com", rating: 4)

# Example to destroy all users matching the given condition using delete_by
  User.delete_by(email: "mit@gmail.com")
  User.delete_by(email: "mit@gmail.com", rating: 4)

MittalPatel-BTC

# Rails 5.2
> User.count
SELECT COUNT(\*) FROM "users"
=> 3

> User.all.touch_all
=> Traceback (most recent call last):1: from (irb):2
NoMethodError (undefined method 'touch_all' for #<User::ActiveRecord_Relation:0x00007fe6261f9c58>)

> User.all.each(&:touch)

MittalPatel-BTC

# Rails 6
> User.count
SELECT COUNT(*) FROM "users"
=> 3

> User.all.touch_all
UPDATE "users" SET "updated_at" = ?  [["updated_at", "2019-04-20 16:10:40.490507"]]
=> 3

MittalPatel-BTC

User.all.touch_all(time: Time.new(2019, 4, 12, 1, 0, 0))
User.all.touch_all(:created_at)

MittalPatel-BTC

# Rails 6
class User < ApplicationRecord
  validates :name, presence: true
end

> user = User.new
=> #<User id: nil, name: nil, email: nil, rating: 0, password: nil, created_at: nil, updated_at: nil>

> user.valid?
=> false

MittalPatel-BTC

# Rails 5.2
class User < ApplicationRecord
  validates :email, presence: true
end

> user = User.new
=> #<User id: nil, name: nil, email: nil, rating: 0, password: nil, created_at: nil, updated_at: nil>

> user.valid?
=> false

MittalPatel-BTC

# Rails 6

> user = User.new
=> #<User id: nil, name: nil, email: nil, rating: 0, password: nil, created_at: nil, updated_at: nil>

> user.valid?
=> false

> user.errors
=> #<ActiveModel::Errors:0x00007fc46700df10 @base=##<User id: nil, name: nil, email: nil, rating: 0, password: nil, created_at: nil, updated_at: nil>, @messages={:email=>["can't be blank"], :password=>["can't be blank"]}, @details={:email=>[{:error=>:blank}], :password=>[{:error=>:blank}]}>