work on notes for 9

Author: Saicheg

materials/9/app/app/models/user.rb

@@ -0,0 +1,2 @@
+class User < ActiveRecord::Base
+end

materials/9/app/db/migrate/20140216101712_create_users.rb

@@ -0,0 +1,12 @@
+class CreateUsers < ActiveRecord::Migration
+  def change
+    create_table :users do |t|
+      t.string :email
+      t.string :name
+      t.integer :age
+      t.string :password
+
+      t.timestamps
+    end
+  end
+end

materials/9/app/db/schema.rb

@@ -0,0 +1,28 @@
+# encoding: UTF-8
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# Note that this schema.rb definition is the authoritative source for your
+# database schema. If you need to create the application database on another
+# system, you should be using db:schema:load, not running all the migrations
+# from scratch. The latter is a flawed and unsustainable approach (the more migrations
+# you'll amass, the slower it'll run and the greater likelihood for issues).
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(version: 20140216101712) do
+
+  # These are extensions that must be enabled in order to support this database
+  enable_extension "plpgsql"
+
+  create_table "users", force: true do |t|
+    t.string   "email"
+    t.string   "name"
+    t.integer  "age"
+    t.string   "password"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
+end

notes/9.md

@@ -26,6 +26,7 @@ create_table :users do |t|
   t.string :name
   t.string :password
   t.string :age
+  t.boolean :not_nerd
 end
 
 create_table :people do |t|
@@ -38,34 +39,34 @@ end
   User.create email: Faker::Internet.email,
   			   name: Faker::Name.name,
   			   password: '123456',
-  			   age: rand(12..90)
+  			   age: rand(12..90),
+  			   not_nerd: true
 end
 
 ```
 
 ### List of methods
-* bind
 * create_with
 * eager_load
 * extending
 * from
-* group
+* group +
 * having
 * includes
 * joins
-* limit
+* limit +
 * lock
-* none
-* offset
-* order
+* none + 
+* offset +
+* order + 
 * preload
 * readonly
 * references
 * reorder + 
-* reverse_order
-* select
-* distinct
-* uniq
+* reverse_order +
+* select + 
+* distinct +
+* uniq +
 * where
 
 ```
@@ -77,9 +78,8 @@ User.find_by(age: 18)
 User.find_or_create_by(email: 'ololol@mail.ru')
 
 User.limit(10)
-User.limit(10).offset(10)
-User.order(:age).limit(10)
-User.order('age DESC')
+User.offset(10)
+User.order(:age)
 ```
 
 ```
@@ -88,11 +88,78 @@ scope = scope.offset(10)
 scope = scope.order(:age)
 scope.reorder(:email).all
 
+User.limit(4).to_sql
+User.limit(4).unscoped.to_sql
+User.limit(4).unscoped.none.to_sql
+
+```
+
+```
+User.order(:age).reverse_order
+User.limit(5).select(:name)
+User.limit(5).pluck(:name)
+User.select(:age).distinct
+User.select(:age).uniq
+User.group(:age).select('COUNT(*) as number, age as age')
+Hash[User.group(:age).select('COUNT(*) as number, age as age').map {|u| [u.age, u.number]}]
+Hash[User.group(:age, :id).having('age > 18').map {|u| [u.age, u.number]}]
+Hash[User.group(:age, :id).having('age > 18').select('COUNT(*) as number, age as age').map {|u| [u.age, u.number]}]
+
+```
+
+```
+User.where(age: 18)
+User.where(age: 18).where(password: '1234')
+User.where(age: 18, email: 'lol@gmail.com')
+age=18; User.where('age >= #{age}');
+User.where('age >= ?', 18)
+Usere.where('age >= ? OR email ILIKE ?, 18, 'test@gmail.com')
+User.where('age < :age, create_at >= :date', {age: 18, date: Time.zone.now})
+
 ```
 
 
 ## Validations
 
+
+* model.errors
+* model.valid? || model.invalid?
+* shebang methods
+* skipping validations
+
+
+```
+class User < ActiveRecord::Base
+  validates_presense_of :name
+  validates :name, presence: true
+  validates :name, absence: true
+  validates :not_nerd, acceptance: true
+  # validates :email, confirmation: true
+  validates :email, format: { with: Devise.regexp}
+  validates :not_nerd, inclusion: { in:[true, false]}
+  validates :name, length: { minimum: 5, maximum: 120 }
+  validates :age, numericality: { only_integer: true, greater_than: 0 }
+   validates :name, uniqueness: { scope: :email, case_sensitive: false }
+   validates :name, presence: true, if: 
+
+end
+
+class GoodnessValidator < ActiveModel::Validator
+  def validate(record)
+    if record.name =~ "Evil"
+      record.errors[:base] << "This person is evil"
+    end
+  end
+end
+ 
+class User < ActiveRecord::Base
+  validates_with GoodnessValidator
+end
+
+
+```
+
+
 ## Relations
 
 * (table_name)_count - Used to cac* he the number of belonging objects on associations.