Rails lite HTTP: Hyper Text Transfer Protocol Hypertext: 可以代表link，超链接。 transfer: 把hypertext 来回传递。 Protocol: 有一定的传递规则。 transfer: request and response HTTP REQUEST 1. action: get/po …

list of good questions about rails so far by Liz Houle QUESTION: When do we use before_action? before_action is considered to be a ‘filter’ in Rails (Action Controller Overview — Ruby on Rails Guides), and it is a method that is run before a controller action (e.g. index, create, update, etc.) in the controller in which it is called…

1. what are AR associations? In Rails, an association is a connection between two Active Record models. Associations make common operations simpler and easier in your code. class Movie < ApplicationRecord has_many :actors end has_many is a typical AR association. The common associations are has_one, has_many, belongs_to, has_one_through, has_many_through... 2. Understanding associations in a SQL perspective

Rails Routes & Controllers Learning Objectives Explain the basics of an HTTP request-response cycle Explain how the request-response cycle works with respect to Rails & MVC Explain what a RESTful API is Build Rails Routes, Controllers & Actions corresponding to the 7 RESTful routes What is a server? Note: The term ‘server’ is used to refer…

exams 周一为了准备周二的考试，作为review day，其实这个形式还是蛮不错的，之前完全不理解ActiveRecord返回的东西，怎么使用，现在这几天下来，基本知道怎么用了。看来这种有考试逼迫的填鸭式教学还是最有效率的。 周二上午讲了关于meta programming的一些内容，我觉得很有用，未来可能会在建立一些自己的类的时候用到。 Learning Objectives Define metaprogramming Identify self in: class definitions class methods instance methods Describe the difference between class variables and class instance variables Know how to use send and define_method (and method_missing if time allows) ********这个是重点。

Active Record II Learning Objectives Understand how powerful active record is AR是什么？一个rails的built-in ORM to manipulate the database, 本质是一个Class， 作用就是以OOP的形式来query database。 Understanding its limitations How to avoid N+1 queries，直接通过includes调取连接数据，避免多次query 数据库。 Recognizing we don’t need to memorize everything ActiveRecord Querying vs SQL Ruby interface for querying database Mirrors SQl queries Pros: less overall database access code, more convenient

Models, migrations & Associations Rails: A server-side MVC web-application framework ****full stack framework***** 如何建立一个新的rails project 都可以 ActiveRecord - an ORM Framework (The M in MVC)

ORM 和 CSS sql 文件的建立： create table plays ( id integer primary key, title text not null, year integer not null, playwright_id integer not null, foreign key (playwrigh …

Introduction to SQL Learning Goals ​ Understand why we need databases 存取数据，数据保存ACID， atomic/consistent/independent/durable Explain “Relational DataBase Management System” 类似mysql，Postgresql这种数据库管理软件 Be able to access data in a database and perform basic operations on the data select from where a=b select from (select from) select name, count* from table group by 1 select name…