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An open journal-- some of it written for you, but most of it is for me.

Rails 1st Lecture

Rails Lecture I - July 2

How the web works:

-the requests we send to other servers have headers with info about the request -you get the response with a header and the body -the body is just text and data with HTML -the communication happens over TCP/IP, namely HTTP - the browser renders the HTML by making it pretty -we use GET, POST, PUT, and DELETE -

4 important HTTP Verbs–> GET- retrieve representation of content POST- Submits data PUT- Update Delete- Deletes a specific resource HTTP is all about applying verbs to nouns.

Convention over configuration -we wants defaults

There are naming schemes such as: all tables pl all models are singular controller songs_controller.rb views songs/

Gems:

pre-packaged piece of software that ruby uses

Config Folder–> where the configuration of our app lives -Database.yaml- this is how we communicate the database

App Folder: spend most of our time in the app directory

MVC:### (7:42 pm)

Models: define how data is created, retrieved, updated and deleted–> the only code that defined these 4 actions are in the model

Controllers: where to send the data to business logic

Views: display logic

Helpers: helper functions for your views db: stores your database and all the instructions for your database

lib: code that you app needs but isn’t part of the request cycle -tasks- background tasks

public dir: any code that doesn’t require the rails stack to run

vendor: any 3rd party library that you didn’t write – similar to the lib directory that you didn’t write

REST:

-Representational State Transfer -URL: unified resources locators - there should be a unified way to expose resources to the world -1st concept: the things we get online are resources– what the server is going to respond with is a representation of the real thing (since it can’t deliver the real thing) -there should be consistency and predictability-

rails generate resource song title:string duration:integer #always singular rails generate scaffold song title:string #in the beginning the first few resources are created by scaffolds

MIGRATIONS:### defines a db strcuture

every resource has it’s own table

SQL:### server query language or standard query language

SCHEMA-### describes the structure of the DB

RAKE:### a ruby library to run background tasks

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rake stats-- gives me stats on the app
rake about--> outputs info about the environment, etc
rake -T --> outputs provides commands

VIDEO 2…

migrations are iterative by nature every migration should one and only one thing

rake db:migrate runs the migration rake db:rollback rolls back the migration

OBJECT ORIENTATION

  • what to create metaphors in our code to representations of the real world
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Song.find(2) #=> finds the object of id 2
Song.all #=> returns all the instances of the class

ORM: object relational mappers

  • a class is to a table : an instance of a class is to a row of a table -every instance is going to wrap a row of a table -one to one relationship between an instance and a row -the library, the ORM, allows you to relate to the objects with knowing how the objects are related

Programming is just codifying procedural knowledge

DOCUMENTATION:

Rails Guides: more like how-tos Rails API: the more technical version

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