Chapter 2

Question 1

when you create new app, what git steps do you need to take:

Answer 1

git init
git add -A
git commit -am “initialize repository”

Question 2

connect new app to github:

Answer 2

create new repository on github manually.
then:
git remote add origin https://github.com/Saweel/toy_app.git

Question 3

how to remove origin from git repo and set another one

Answer 3

git remote set-url origin newURL

Question 4

data model

Answer 4

representation of the structures needed by our application. conceptual model of how data items relate to each other

Question 5

data model for toy_app

Answer 5

microblog with users and short microposts.

Question 6

data model for users:

Answer 6

unique integer identifier id, name, email

Question 7

data model for microposts:

Answer 7

id and a content field for the text. also a user_id to associate each micropost with a particular user

Question 8

User resource:

Answer 8

think of users as objects that can be created, read, updated, deleted through the web via the HTTP protocol (created using scaffoldin)

Question 9

generate user with name and email using scaffolding

Answer 9

rails generate scaffold User name:string email:string

Question 10

update the database in rails after creating a new user data model

Answer 10

bundle exec rake db:mirate

Question 11

what is “make”?

Answer 11

unix, make utility is used to build executable programs from source code.

Question 12

Rake:

Answer 12

rake is rubys make, a make-like language written in ruby. uses rake for little administrative tasks necessary developing database-backed web application.

Question 13

bundle exec rake -T db

Answer 13

list of database tasks

Question 14

bundle exec rake -T

Answer 14

all the rake tasks available

Question 15

URL/users

Answer 15

index, page to list all users

Question 16

URL/users/1

Answer 16

show, page to show user with id 1

Question 17

URL/users/new

Answer 17

new, page to make new user

Question 18

URL/users/1/edit

Answer 18

edit, page to edit user with id 1

Question 19

what is the 1 mean in URL/users/1

Answer 19

the id attribute of the user

Question 20

in terms of MVC, describe the results of a typical browser hit- a visit to the user index page at /users (BIG ANSWER)

Answer 20

1. browser issues request for the /users URL
2. Rails routes /users to the index action in the Users controller
3. index action asks User model to retrieve all users
4. User models pulls all the users from the database
5. User model returns the list of users to the controller
6. controller captures users in the @users variable, which is passed to the index view
7. view uses embedded ruby to render the page as HTML
8. controller passes the HTML back to the browser

Question 21

routes.rb, explain “resources :users”

Answer 21

creates the mapping of user URLs to controller actions for the User resource.

Question 22

add a root route for users

Answer 22

root ‘users#index’

Question 23

rails: index,new,show,edit correspond to pages. describe create, update, and destroy actions

Answer 23

they dont typically render pages (although they can); main purpose is to modify information about users in the database

Question 24

index,show,new,create,edit,update,destroy are actions in users_controller. describe the http request for each

Answer 24

index -> get
show -> get
new -> get
create -> post
edit -> get
update -> patch
destroy -> delete

Question 25

REST define (simple)

Answer 25

REpresentational State Transer (rest). architectual style for developing distributed, networked systems and software applications.

Question 26

what does REST mean in the context of rails

Answer 26

application components(users and microposts) are modeled as resources that can be created, read, updated, and deleted - operations that correspond both to the CRUD operations of relational database and to the four fundamental HTTP request methods: POST, GET, PATCH, DELETE.

Question 27

@users

Answer 27

variables with @, are instance variables, and are automatically available in the views

Answer 28

iterates through each object stored in @users

Question 29

weaknesses of this User resource

Answer 29

``` no data validations no authentication no tests no style or layout no real understanding ```

Question 30

generate a micropost with a user id and content text

Answer 30

rails genrate scaffold Micropost content:text user_id:integer

Question 31

validate micropost to accept 140 characters for the content

Answer 31

in micropost.rb: | validates :content, length: { maximum: 140 }

Question 32

create associations between user having many microposts and microposts belonging to one user

Answer 32

``` user.rb: has_many :microposts ------------------------- micropost.rb: belongs_to :user ```

Question 33

class User

Answer 33

User model inherits from ActiveRecord::Base, which is a base class for models provided by ActiveRecord (which lets us gain the ability to communicate with the database, treat database columns as ruby attributes, ect.)

Question 34

class UsersController

Answer 34

User inherits from ApplicationController, which inherits from ActionController::Base (controllers gain large amounts of functionality by inhering from a base class, including ability to manipulate model objects, filter inbround HTTP requests, render views as HTML.)

Question 35

heroku wont work if you just push it. what must you do so the app works correctly (hint: database)

Answer 35

you need to get the applications database to work, so you need to migrate the production database: heroku run rake db:migrate

Question 36

scaffolding strengths:

Answer 36

``` high level overview of rails introduction to mvc first taste of REST beginning data modelling live, database-backed web application in production ```

Question 37

scaffolding weaknesses:

Answer 37

``` no custom layout no static pages (home or about) no user passwords no images no login no security no automatic user/micropost association no notion of following no micropost feed no meaninful tests NO REAL UNDERSTANDING ```